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Convergent validity of the aberrant behavior checklist and behavior problems inventory with people with complex needs
Research in Developmental Disabilities 29 (2008) 45–60
Convergent validity of the aberrant behavior checklist and behavior problems inventory with people with complex needs§ Jennie Hill a, Stephanie Powlitch b, Frederick Furniss c,d,* a
Nottinghamshire Healthcare NHS Trust, Rampton Hospital, Retford, UK b Norwich Primary Care NHS Trust, Norwich, UK c The Hesley Group, Doncaster, UK d School of Psychology, University of Leicester, UK Received 3 October 2006; accepted 10 October 2006
Abstract The current study aimed to replicate and extend Rojahn et al. [Rojahn, J., Aman, M. G., Matson, J. L., & Mayville, E. (2003). The aberrant behavior checklist and the behavior problems inventory: Convergent and divergent validity. Research in Developmental Disabilities, 24, 391–404] by examining the convergent validity of the behavior problems inventory (BPI) and the aberrant behavior checklist (ABC) for individuals presenting with multiple complex behavior problems. Data were collected from 69 children and adults with severe intellectual disabilities and challenging behavior living in residential establishments. MANCOVA analyses showed that individuals with elevated BPI stereotyped behavior subscale scores had higher scores on ABC lethargy and stereotypy subscales, while those with elevated BPI aggressive/destructive behavior subscale scores obtained higher scores on ABC irritability, stereotypy and hyperactivity subscales. Multiple regression analyses showed a corresponding pattern of results in the prediction of ABC subscale scores by BPI subscale scores. Exploratory factor analysis of the BPI data suggested a six-factor solution with an aggressive/destructive behavior factor, four factors relating to stereotypy, and one related to stereotypy and self-injury. These results, discussed with reference to Rojahn et al. [Rojahn, J., Aman, M. G., Matson, J. L., & Mayville, E. (2003). The aberrant behavior checklist and the behavior problems inventory: Convergent and divergent validity. Research in Developmental Disabilities, 24, 391–404], support the existence of relationships between specific subscales of the two instruments in
§ A preliminary version of this paper was presented to the 2004 World Congress of the International Association for the Scientific Study of Intellectual Disability. * Corresponding author at: The Hesley Group, Mallard House, Sidings Court, Doncaster DN4 5NU, UK. Tel.: +44 1302 386900; fax: +44 1302 386901. E-mail address: [email protected] (F. Furniss).
0891-4222/$ – see front matter # 2006 Elsevier Ltd. All rights reserved. doi:10.1016/j.ridd.2006.10.002
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addition to an overall association between total scores related to general severity of behavioral disturbance. # 2006 Elsevier Ltd. All rights reserved. Keywords: Aberrant behavior checklist; Assessment; Problem behavior; Behavior problems inventory; Validity
1. Introduction Several instruments currently exist for assessing behavioral disorders in individuals with severe intellectual disabilities. These instruments are widely used as screening tools for detecting potential challenging behaviors, developing and evaluating intervention strategies, and clinical research. One reason challenging behaviors such as aggressive outbursts, stereotyped behaviors and self-injury routinely need to be assessed in individuals with severe intellectual disabilities is because they can impede successful integration into the community (Rojahn, Aman, Matson, & Mayville, 2003). Current behavioral assessment scales can be distinguished into two categories by their scope. Generalised behavior rating scales assess a number of different conditions, each of which consists of a number of sub-conditions. For example, psychopathology is a condition that consists of sub-conditions such as mania, mood disorders and anxiety. Although generalised rating scales encompass extensive ranges of psychopathology, they are typically restricted to relatively few items per clinical condition and thus can be potentially unreliable (Rojahn, Matson, Lott, Esbensen, & Smalls, 2001). Specialised behavior rating scales on the other hand assess only narrowly defined conditions, such as aggression. The aberrant behavior checklist (ABC) (Aman & Singh, 1986) is a generalised behavior rating scale which was developed inductively, i.e. the subscales included in the ABC (irritability, lethargy, stereotypy, hyperactivity and inappropriate speech) were developed by factor analysing reports of clinically observed behaviors. A number of psychometric studies have subsequently confirmed the factor validity of the ABC in a variety of population groups (Aman, Burrow, & Wolford, 1995; Bihm & Poindexter, 1991; Marshburn & Aman, 1992), although Brown, Aman, and Havercamp (2002) found a four-factor model lacking an ‘‘inappropriate speech’’ factor in a population of children and adolescents in special education settings. A number of studies have found the criterion validity of the ABC to range from adequate to very good (Aman, Singh, Stewart, & Field, 1985; Rojahn & Helsel, 1991). The ABC has also been found to be reliable. For example, Aman et al. (1985) found the ABC to have very good internal consistency (coefficient alphas ranged from 0.86 to 0.94 across subscales), acceptable interrater reliability (mean Spearman correlation coefficients across pairs of raters ranged from 0.55 to 0.69 across subscales) and very good test–retest reliability (Spearman correlation coefficients between pairs of scores given by raters 4 weeks apart ranged from 0.96 to 0.99 across subscales). Aman, Singh, and Turbott (1987), using Pearson correlations to assess agreement, found generally comparable levels of inter-rater reliability but lower, although still very acceptable, test–retest reliability. The behavior problems inventory (BPI) (Rojahn et al., 2001) is a specialised behavior rating scale. Item selection for the subscales of the BPI was achieved by a literature review of studies assessing problem behavior instruments. The BPI was originally a 32-item rating scale containing only items relating to self-injurious behavior and stereotypies (Rojahn, 1984, 1986) but has been developed over the years, including the addition of a social maladaptation dimension
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to the scale (McGrew, Ittenbach, Bruininks, & Hill, 1991) and the replacement of the original stereotypies subscale with the independently developed ‘‘stereotyped behavior scale’’ (Rojahn, Matlock, & Tasse´, 2000; Rojahn, Tasse´, & Sturmey, 1997). Sturmey, Sevin, and Williams (1995) found the BPI to have good test–retest and inter-rater reliability, although variable levels of reliability across items and subscales had previously been found by the original author (Rojahn, Polster, & Mulick, 1989). Internal and criterion-related validity levels for the BPI have been found to be modest to good (Rojahn et al., 2001). Factor analysis of the BPI on the other hand has yielded varied results. Sturmey, Fink, and Sevin (1993) used principal components factor analysis which yielded a two-factor structure. These two factors closely resembled the BPI aggression and self-injury subscales, but no factor corresponding to the stereotypy subscale was found. In a replication study, Sturmey et al. (1995) proposed a two- or three-factor structure. In this study, the factors yielded contained only items relating to self-injury, thus neither an aggression factor nor a stereotypy factor was found. These studies also found the self-injury subscale to be multi-factorial, suggesting that self-injury items do not form a single dimension (Sturmey et al., 1993, 1995). However, all of these factor analyses were conducted on the original BPI (Rojahn, 1984, 1986), not the revised one (Rojahn et al., 2001). Rojahn et al. (2001) performed a confirmatory factor analysis on data from 432 individuals with intellectual disabilities, assuming 3 oblique factors corresponding to the BPI subscales, and found mean factor loadings of 0.34 for the SIB, 0.38 for the stereotyped behavior, and 0.54 for the aggression/ destruction subscales. To date, however, no exploratory factor analysis appears to have been published on the current BPI. Previous research (Rojahn et al., 2003) has demonstrated selective relationships between subscale scores on the BPI and the ABC, supporting the convergent validity of the scales. This research however included many participants with BPI scores of 0, indicating low levels of behavioral disturbance in these individuals. The aims of the present study were thus: (1) to examine the convergent validity of the BPI and the ABC when used to assess individuals presenting with multiple complex behavior problems and (2) in view of the variability in previous findings concerning the factor structure of the BPI, to conduct a factor analysis using principal components analysis to investigate the factor structure of the current BPI when used with this population group. 2. Method 2.1. Participants Participants were 69 children and adults (58 males and 11 females) with severe intellectual disabilities and challenging behavior living in one of four residential establishments in England. The mean age of the participants was 18 years and 5 months (minimum 9 years and 4 months— maximum 29 years and 7 months). Each participant was assessed using either the AAMR adaptive behavior scale—school (Lambert, Nihira, & Leland, 1993) or the AAMR adaptive behavior scale—residential (Nihira, Leland, & Lambert, 1993), dependent upon whether they were below or above 18 years of age respectively, to assess their adaptive abilities. The mean independent functioning standard score of the participants was 9 (minimum 1—maximum 12) and the mean language development standard score of the participants was 7 (minimum 2— maximum 13). Scores from routine assessments using the Diagnostic Assessment for the Severely Handicapped II (DASH-II) (Matson, 1995) were available for 49 participants. Mean DASH-II PDD/Autism subscale score for participants was 7 (range 2–12).
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Data for seven additional participants (five males and two females) for whom BPI, but not ABC, data were available were used in factor analysis of BPI items. The mean age of the additional participants was 16 years 11 months, the mean independent functioning standard score of the four additional participants for whom scores were available was 9, and their mean language development score was 8. 2.2. Instruments 2.2.1. The behavior problems inventory (BPI) The BPI is a 52-item specialised (Rojahn et al., 2003) behavior rating scale designed to assess specific problem behaviors in individuals with intellectual and developmental disabilities. The BPI used in the present study was the BPI-01 edition, described by Rojahn et al. (2001). The three subscales of the BPI-01 are: (i) self-injurious behavior (14 items), (ii) stereotyped behavior (24 items) and (iii) aggressive/destructive behavior (11 items). Each subscale also has a residual item, so that respondents can include any behavior not included in the list of items that meets the definition of the targeted problem behavior (e.g. ‘‘other stereotypy’’). Each subscale item is scored on two scales: (a) a frequency scale ranging from never: 0, through to hourly: 4 (5-point scale) and (b) a severity scale ranging from no problem: 0, through to severe problem: 3 (4-point scale). The behavior must have appeared at least once over the past 2 months in order for it to be rated (i.e. given a frequency score greater than 0). 2.2.2. The aberrant behavior checklist (ABC) The ABC (Aman & Singh, 1986) is a factor analytically derived 58-item generalised behavior rating scale. The ABC was originally designed to aid in the evaluation of psychotropic drug treatments for individuals with severe and profound intellectual and developmental disabilities, although it can also be used as a general assessment tool for problem behaviors. The five subscales of the ABC are: (i) irritability (15 items), (ii) lethargy (16 items), (iii) stereotypy (7 items), (iv) hyperactivity (16 items) and (v) inappropriate speech (4 items). Each subscale item is scored on a severity scale ranging from not at all a problem: 0, through to the problem is severe in degree: 3 (4-point scale). The behavior must have appeared at least once over the past 4 weeks in order for it to be rated (i.e. given a severity score greater than 0). 2.3. Interviewers and respondents Either a clinical psychologist or a psychology graduate administered the BPI. Psychology graduates administered the ABC. The respondents were the direct support staff members who had worked with each participant the longest. 3. Results Data analysis was performed on both the total scores and the subscales for each instrument. As with Rojahn et al.’s (2003) study, high (Pearson) correlations were found between the frequency and severity scales of the BPI (0.88 for self-injurious behavior, 0.92 for stereotyped behavior and 0.80 for aggressive/destructive behavior, n = 69). For this reason, only the frequency scales of the BPI were used in further analyses. Table 1 shows the means, standard deviations, minima and maxima of the ABC and BPI total and subscale scores. Neither the ABC nor the BPI had normally distributed data. However, this feature is characteristic of maladaptive behavior data. In
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Table 1 Means, standard deviations, minima and maxima for BPI and ABC scores (n = 69) Mean
S.D.
Minimum
Maximum
BPI Total score
46.19
21.07
10
109
Subscales Self-injurious behavior Stereotyped behavior Aggressive/destructive behavior
8.29 26.20 11.70
5.45 16.47 8.35
0 0 0
26 80 38
ABC Total score
51.83
22.12
6
100
Subscales Irritability Lethargy Stereotypy Hyperactivity Inappropriate speech
16.46 10.68 4.91 16.42 3.35
8.73 7.23 4.02 9.37 3.70
0 0 0 2 0
40 33 15 36 12
general, these data sets have positive skewness and kurtosis (Rojahn et al., 2003). This pattern was found in the present data set for BPI total scores (skewness of 0.71 and kurtosis of 0.52) but not for the ABC total scores (skewness of 0.11 and kurtosis of 0.77). 3.1. Preliminary correlations The first set of analyses obtained Pearson correlations between the BPI total and subscale scores and ABC total and subscale scores (see Table 2). Significant positive correlations were found between total BPI score and total ABC score, between total BPI score and ABC irritability, lethargy, stereotypy and hyperactivity subscale scores, between total ABC score and BPI stereotyped behavior subscale score, BPI self-injurious behavior subscale score and ABC irritability subscale score, BPI stereotyped behavior subscale score and ABC stereotypy and lethargy subscale scores, and BPI aggressive/destructive behavior subscale score and ABC irritability and hyperactivity subscale scores. A significant negative correlation was found between BPI aggressive/destructive behavior subscale score and ABC stereotypy subscale score. Significant correlations were not found between any other BPI and ABC subscale scores. Table 2 Pearson correlations between BPI and ABC subscale and total scores BPI total score ABC ABC ABC ABC ABC ABC a b
total score irritability lethargy stereotypy hyperactivity inappropriate speech
0.37a 0.27b 0.29b 0.36a 0.26b 0.07
BPI self-injurious behavior 0.22 0.29b 0.19 0.13 0.04 0.04
Correlation is significant at the 0.01 level (two-tailed). Correlation is significant at the 0.05 level (two-tailed).
BPI stereotyped behavior 0.29b 0.09 0.31b 0.55a 0.18 0.13
BPI aggressive/ destructive behavior 0.22 0.32a 0.02 0.26b 0.29b 0.06
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3.2. Categorical or group comparisons These analyses were ‘designed to test the hypothesis that individuals with elevated BPI subscale scores should have higher scores on some ABC subscale scores, as compared to individuals with low BPI scores’ (Rojahn et al., 2003, p. 395). Two sets of analyses were performed. For the first set of analyses, the sample was divided into two groups: a ‘‘moderate behavior disturbance’’ group containing participants who had no items with a score of 4 on either the BPI self-injurious behavior subscale or the BPI aggressive/destructive behavior subscale (n = 49) and a ‘‘severe behavior disturbance’’ group containing participants who had at least one item with a score of 4 on either the BPI self-injurious behavior subscale or the BPI aggressive/ destructive behavior subscale (n = 20). Fig. 1 displays the ABC mean subscale scores for these two groups. A MANOVA conducted with the ABC subscale scores as the dependent variables yielded a non-significant multivariate effect (Wilks’ l = 0.97, p = 0.87). None of the ABC subscales showed significant group differences. In the second set of analyses, ‘the unique effect of each of the three BPI subscale scores on the ABC subscale scores was determined, while controlling for the variance of the two other BPI subscales’ (Rojahn et al., 2003, p. 395). Three MANCOVAs were computed, one for each subscale: (i) The BPI self-injurious behavior (SIB) dichotomous subscale score (group 1: SIB score < SIB mean score, n = 39; group 2: SIB score > SIB mean score, n = 30) was the grouping variable, the ABC subscale scores were the dependent variables and the BPI
Fig. 1. Mean ABC subscale scores for ‘‘moderate behavior disturbance’’ group (participants with no items with a score of 4 on either the BPI self-injurious behavior subscale or the BPI aggression/destruction subscale) and ‘‘severe behavior disturbance’’ group (participants with at least one item with a score of 4 on either the BPI self-injurious behavior subscale or the BPI aggression/destruction subscale).
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Table 3 Summary table of MANCOVA results Tests MANCOVA: SIB < SIB mean vs. SIB > SIB mean Multivariate: Wilks’ l = 0.93, between-subjects ABC irritability ABC lethargy ABC stereotypy ABC hyperactivity ABC inappropriate speech MANCOVA: STER < STER mean vs. STER > STER mean Multivariate: Wilks’ l = 0.70, between-subjects ABC irritability ABC lethargy ABC stereotypy ABC hyperactivity ABC inappropriate speech
F
d.f.
Significance
0.97 0.16 0.13 0.88 2.23 0.09
5/61 1/65 1/65 1/65 1/65 1/65
0.44 0.70 0.72 0.35 0.14 0.76
5.14 0.01 6.73 19.12 0.91 1.59
5/61 1/65 1/65 1/65 1/65 1/65
0.001 0.92 0.01 0.001 0.34 0.21
5/61 1/65 1/65 1/65 1/65 1/65
0.001 0.02 0.30 0.05 0.01 0.44
MANCOVA: AGG/DES < AGG/DES mean vs. AGG/DES > AGG/DES mean Multivariate: Wilks’ l = 0.72, between-subjects 4.84 ABC irritability 6.25 ABC lethargy 1.12 ABC stereotypy 4.11 ABC hyperactivity 8.61 ABC inappropriate speech 0.61
SIB, BPI self-injurious behavior subscale score; STER, BPI stereotyped behavior subscale score; AGG/DES, BPI aggressive/destructive behavior subscale score.
stereotyped behavior and aggressive/destructive behavior subscale scores were the covariates. The overall multivariate effect was found to be non-significant (Wilks’ l = 0.93, p = 0.44) and participants in these SIB groups did not differ with regard to any of the ABC subscale scores (Table 3, first panel). (ii) The BPI stereotyped behavior (STER) dichotomous subscale score (group 1: STER score < STER mean score, n = 35; group 2: STER score > STER mean score, n = 34) was the grouping variable, the ABC subscale scores were the dependent variables and the BPI self-injurious behavior and aggressive/destructive behavior subscale scores were the covariates. The overall multivariate effect was found to be significant (Wilks’ l = 0.70, p = 0.001) as were the effects for the ABC lethargy and stereotypy subscales. Participants in these STER groups did not differ with regard to their ABC irritability, hyperactivity and inappropriate speech subscales scores (Table 3, second panel). (iii) The BPI aggressive/destructive behavior (AGG/DES) dichotomous subscale score (group 1: AGG/DES score < AGG/DES mean score, n = 40; group 2: AGG/DES score > AGG/ DES mean score, n = 29) was the grouping variable, the ABC subscale scores were the dependent variables and the BPI self-injurious behavior and stereotyped behavior subscale scores were the covariates. The overall multivariate effect was found to be significant (Wilks’ l = 0.72, p = 0.001) as were the effects for the ABC irritability, stereotypy and hyperactivity subscales. Participants in these AGG/DES groups did not differ with regard to their ABC lethargy and inappropriate speech subscales scores (Table 3, third panel).
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3.3. Multiple regression Five multiple regression analyses were conducted to assess whether any of the five ABC subscales would be significantly predicted by any of the three BPI subscales. The BPI subscales were the independent variables and the ABC subscales were the dependent variables. Table 4 summarises the results of these analyses. The first regression equation, with the ABC irritability subscale as the dependent variable, was significant (F = 3.48, d.f. = 3, 65, p < 0.05). This equation was able to explain 10% of the variance in ABC irritability subscale score. However, inspection of the beta weights reveals that only the BPI aggressive/destructive behavior subscale made a significant contribution to the prediction of the ABC irritability subscale. The second regression equation, with the ABC lethargy subscale as the dependent variable, was significant (F = 2.75, d.f. = 3, 65, p = 0.05). This equation was able to explain 7% of the variance in ABC lethargy subscale score. Inspection of the beta weights reveals that only the BPI stereotyped behavior subscale made a significant contribution to the prediction of the ABC lethargy subscale. The third multiple regression equation, with the ABC stereotypy subscale as the dependent variable, was highly significant (F = 13.96, d.f. = 3, 65, p < 0.001). This equation was able to explain 36% of the variance in the ABC stereotypy subscale score. Inspection of the beta weights reveals that both the BPI stereotyped behavior and the BPI aggressive/destructive behavior subscales made significant contributions to the prediction of the ABC stereotypy subscale. The fourth regression equation, with the ABC hyperactivity subscale as the dependent variable, was also significant (F = 3.00, d.f. = 3, 65, p < 0.05). However, this equation was only able to explain 8% of the variance in the ABC hyperactivity subscale score. Inspection of the beta weights reveals that only the BPI aggressive/destructive behavior subscale made a significant
Table 4 Prediction of ABC subscale scores by BPI subscales: multiple regression analyses R2 adjusted
BPI subscale
b
ABC irritability
0.10
*
Self-injurious behavior Stereotyped behavior Aggressive/destructive behavior
0.19 0.04 0.25*
ABC lethargy
0.07*
Self-injurious behavior Stereotyped behavior Aggressive/destructive behavior
0.15 0.28* 0.04
ABC stereotypy
0.36***
Self-injurious behavior Stereotyped behavior Aggressive/destructive behavior
0.14 0.53*** 0.32**
ABC hyperactivity
0.08*
Self-injurious behavior Stereotyped behavior Aggressive/destructive behavior
0.11 0.19 0.32*
ABC inappropriate speech
0.02
Self-injurious behavior Stereotyped behavior Aggressive/destructive behavior
0.05 0.14 0.05
* ** ***
p < 0.05. p < 0.01. p < 0.001.
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contribution to the prediction of the ABC hyperactivity subscale. The fifth and final regression equation, with the ABC inappropriate speech subscale as the dependent variable, was not significant (F = 0.52, d.f. = 3, 65, p = 0.67). In summary, the BPI stereotyped behavior subscale significantly predicted both the ABC lethargy subscale and the ABC stereotypy subscale. The BPI aggressive/destructive behavior subscale significantly predicted the ABC irritability subscale, the ABC stereotypy subscale and the ABC hyperactivity subscale. The BPI self-injurious behavior subscale however did not predict any of the ABC subscales.
Table 5 Factor analysis of all BPI items with loadings of items on to factors BPI item (and subscale)
Factor I
41. Hitting others (AGG/DES) 45. Grabbing/pulling others (AGG/DES) 42. Kicking others (AGG/DES) 43. Pushing others (AGG/DES) 46. Scratching others (AGG/DES) 51. Being mean or cruel (AGG/DES) 48. Spitting on others (AGG/DES) 47. Pinching others (AGG/DES) 44. Biting others (AGG/DES) 26. Yelling/screaming (STER) 50. Destroying things (AGG/DES) 31. Complex hand movements (STER) 33. Sustained finger movements (STER) 25. Repetitive hand movements (STER) 22. Repetitive body movements (STER) 39. Waving hands (STER) 20. Rolling head (STER) 19. Waving or shaking arms (STER) 37 Clapping hands (STER) 28. Bouncing around (STER) 16. Rocking back & forth (STER) 30. Bursts of running around (STER) 23. Pacing (STER) 24. Twirling things (STER) 34. Rubbing self (STER) 21. Whirling, turning on spot (STER) 18. Spinning own body (STER) 9 Pulling finger or toe nails (SIB) 39 Waving hands (STER) 4. Self-scratching (SIB) 6. Self-pinching (SIB) 12. Hair pulling (SIB) 13. Extreme drinking (SIB) 27. Sniffing own body (STER) 17. Sniffing objects (STER) 10. Inserting fingers into body openings (SIB)
0.837 0.771 0.737 0.736 0.697 0.662 0.637 0.525 0.459 0.382 0.346
II
III
IV
V
VI
0.321
0.327 0.809 0.807 0.781 0.650 0.532 0.434 0.404
0.338
0.343
0.461 0.753 0.711 0.619 0.618 0.477 0.439 0.349
0.359 0.836 0.836 0.374 0.352 0.851 0.775 0.557 0.432 0.810 0.783 0.453
SIB, BPI self-injurious behavior subscale; STER, BPI stereotyped behavior subscale score; AGG/DES, BPI aggressive/ destructive behavior subscale score.
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3.4. Factor analysis of BPI data In view of the limited amount of information available on the factor structure of the BPI, an exploratory factor analysis was undertaken. As noted above, this analysis used BPI data from 76 participants. Principal components analysis with varimax rotation was used as this method had been used in previous analyses of the factor structure of the original BPI. Fifteen factors with initial eigenvalues exceeding 1 were identified, of which the first six had eigenvalues exceeding 2 and were readily interpretable; these six accounting for 10, 7.8, 6.2, 5.2, 5.2 and 4.8% of the variance, respectively. Table 5 lists the items with a factor loading of 0.3. All but one of the items from the BPI aggressive/destructive behavior subscale loaded on to the first factor identified. Factors II, III, IV and VI received loadings predominantly from the stereotyped behavior subscale of the BPI, with factor II mainly relating to fine motor stereotypies, factor III to overactivity/gross motor stereotypy, factor IV to whirling/ spinning and factor VI to sniffing and rubbing. Factor V predominantly received loadings from items relating to scratching, pinching and hair-pulling from the self-injurious behavior subscale. A further analysis, again using principal components analysis with varimax rotation, was carried out on items from the self-injurious behavior subscale alone. Five factors with eigenvalues exceeding 1 were identified, with eigenvalues of 3.11, 1.85, 1.46, 1.25 and 1.09, respectively, and accounting for 20.6, 11.9, 11.6, 9.8 and 8.6% of the variance. Table 6 presents the pattern of factor loadings of 0.3. Factor I related to self-biting, scratching, pinching, hair-pulling and self-hitting; factor II to inappropriate placing of fingers and objects in body cavities (including pica), teeth grinding, self-scratching (negatively) and selfhitting; factor III related to vomiting/regurgitation and inappropriate placing of objects/ materials in body cavities (including pica). The remaining two factors each received substantial loadings from two items only, in the case of factor IV air-swallowing and excessive drinking, and in the case of factor 5 pulling nails and inserting fingers into body openings.
Table 6 Factor analysis of BPI self-injurious behavior subscale items with loadings of items on to factors BPI self-injurious behavior subscale item
Factor I
6. Self-pinching 12. Hair pulling 2. Hitting head with hand/body 4. Self-scratching 1. Self-biting 3. Hitting body with hand/body 7. Pica, mouthing or swallowing objects 14. Teeth grinding 10. Inserting fingers into body openings 8. Inserting objects into body openings 5. Vomiting or rumination 11. Air swallowing 13. Extreme drinking 9. Pulling finger or toe nails
0.792 0.703 0.660 0.659 0.650 0.612
II
III
IV
V
0.468 0.342 0.624 0.571 0.442
0.316 0.375 0.507 0.854 0.723 0.823 0.690 0.879
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4. Discussion Previous research has demonstrated selective relationships between subscale scores on the BPI and the ABC in a sample that included many participants with low levels of behavioral disturbance, thus supporting the convergent validity of the scales when conducted on individuals from this population (Rojahn et al., 2003). The current study aimed to replicate Rojahn et al.’s methodology to examine the convergent validity of the BPI and the ABC when used to assess individuals presenting with multiple complex behavior problems. The mean BPI and ABC scores of individuals in the two studies are indicative that participants in the current study presented with significantly higher levels of behavioral disturbance (BPI mean score = 46; ABC mean score = 52) than participants in Rojahn et al.’s (2003) study (BPI mean score = 8; ABC mean score = 12). Rojahn et al. (2003) utilised three sets of analyses to test the hypothesis that individuals with elevated BPI subscale scores should have higher scores on some ABC subscales. Firstly, they split the sample into two sub-groups, (a) BPI total score of 0 and (b) BPI score greater than 0, and compared their ABC subscale scores (using MANOVA). The multivariate test was found to be significant, as were the between-subject tests for the ABC irritability, lethargy, stereotypy and hyperactivity subscales. The two groups were found not to differ significantly in their inappropriate speech scores. These results confirmed that individuals with elevated BPI scores obtained higher ABC subscale scores than individuals with low BPI scores. The current study was not able to replicate this part of Rojahn et al.’s analyses as the lowest obtained BPI score was 10. Correlations between the BPI subscale scores and the ABC subscale scores were thus obtained in the current study to replace Rojahn et al.’s two-group comparison. These correlations indicated: (i) that individuals with elevated BPI scores obtained higher ABC scores and (ii) that individuals with elevated BPI subscale scores obtained higher scores on some of the ABC subscales (significant positive correlations between: (a) BPI self-injurious behavior subscale scores and ABC irritability subscale scores, (b) BPI stereotyped behavior subscale scores and ABC stereotypy subscale scores, (c) BPI stereotyped behavior subscale scores and ABC lethargy subscale scores, (d) BPI aggressive/destructive behavior subscale scores and ABC hyperactivity subscale scores and (e) BPI aggressive/destructive behavior subscale scores and ABC irritability subscale scores). Thus, the results of the correlations in the current study appear to be consistent with the results of the first set of analyses conducted by Rojahn et al. (2003). The second set of analyses utilised by Rojahn et al. (2003) to test the hypothesis that individuals with elevated BPI subscale scores should have higher scores on some ABC subscales involved breaking the sample down into three sub-groups: (a) BPI total score of 0, (b) BPI scores greater than 0, but without a score of 4 on either the self-injurious behavior or the aggressive/ destructive behavior subscales and (c) BPI score greater than 0, with at least one score of 4 on either the self-injurious behavior or the aggressive/destructive behavior subscales. A MANOVA was then conducted to compare their ABC subscale scores. As with the first set of analyses, the multivariate test was found to be significant, as were the between-subject tests for the ABC irritability, lethargy, stereotypy and hyperactivity subscales. The three groups were found not to differ significantly in their inappropriate speech scores. These results again confirmed that individuals with elevated BPI scores have higher ABC subscale scores (except for the inappropriate speech subscale) than individuals with low BPI scores. The current study replicated these analyses as far as possible but, as mentioned previously, it was not possible to create a sub-group of individuals with a BPI score of 0. Thus, a two-group comparison was conducted comparing ABC subscale scores for a moderate behavior disturbance
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group with BPI scores greater than 0, but without a score of 4 on either the self-injurious behavior or the aggressive/destructive behavior subscales, and a severe behavior disturbance group with at least one score of 4 on either the self-injurious behavior or the aggressive/destructive behavior subscales of the BPI. A MANOVA was conducted to compare the two sub-groups’ ABC subscale scores. However, contrary to the findings of Rojahn et al. (2003), the multivariate test in the current study was found to be non-significant and none of the ABC subscales were found to show significant group differences. This discrepancy in findings is likely to be a function of the population groups being examined in each of the studies. The mean ABC subscale scores of the ‘moderate behavior disturbance’ group in the current study were all higher than the corresponding mean ABC subscale scores of the ‘severe behavior disturbance’ group in Rojahn et al.’s (2003) study. This indicates that individuals in the ‘moderate behavior disturbance’ group in the current study were generally more disturbed than the participants in the ‘severe behavior disturbance’ group in Rojahn et al.’s (2003) study. Thus, individuals in the current study received relatively high scores on the ABC subscales regardless of whether or not they received a score of 4 on either the BPI self-injurious behavior or the BPI aggressive/destructive behavior subscales. The third set of analyses utilised by Rojahn et al. (2003) was designed to determine the unique effect of each of the three BPI subscale scores on the ABC subscale scores, while controlling the variance of the other two BPI subscales. In each MANCOVA, the grouping variable was the BPI dichotomous subscale score (group 1: BPI subscale score = 0; group 2: BPI subscale score > 0). In each MANCOVA, the overall multivariate effect was found to be significant. Participants in the BPI self-injurious behavior groups were found to differ significantly with regard to their ABC irritability, lethargy and hyperactivity scores, participants in the BPI stereotyped behavior groups were found to differ significantly with regard to their ABC irritability, lethargy, stereotypy and hyperactivity scores, and participants in the BPI aggressive/destructive behavior groups were found to differ significantly with regard to their irritability, hyperactivity and inappropriate speech scores. These results are indicative that the BPI and the ABC cross-validated each other in a convergent manner when conducted on individuals with low to moderate levels of behavioral disturbance. The current study replicated these analyses, but utilised different group division points when conducting the MANCOVAs (group 1: BPI subscale score < BPI subscale mean score; group 2: BPI subscale score > BPI subscale mean score). This amendment was necessary due to there being very few participants in the current study with BPI subscale scores of 0. The overall multivariate effect was only found to be significant when the BPI stereotyped behavior and the BPI aggressive/destructive behavior dichotomous subscale scores were utilised as the grouping variable, but not when the BPI self-injurious behavior dichotomous subscale score was utilised as the grouping variable. Participants in the BPI stereotyped behavior groups were found to differ significantly with regard to their ABC lethargy and stereotypy scores, and participants in the BPI aggressive/destructive behavior groups were found to differ significantly with regard to their ABC irritability, stereotypy and hyperactivity scores. Participants in the BPI self-injurious behavior groups were not found to differ significantly with regard to any of their ABC subscale scores. Some of these results are consistent with those obtained by Rojahn et al. (2003) but there are also some discrepancies. Both the current study and Rojahn et al.’s (2003) study found that participants in the BPI stereotyped behavior groups differed significantly with respect to their ABC lethargy and stereotypy scores, and that participants in the BPI aggressive/destructive behavior groups differed significantly with respect to their ABC irritability and hyperactivity scores. However, the current study additionally found that participants in the BPI aggressive/ destructive behavior groups differed significantly with respect to their ABC stereotypy scores.
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Conversely, Rojahn et al. (2003) found that participants in the BPI aggressive/destructive behavior groups also differed significantly with respect to their ABC inappropriate speech scores, that participants in the BPI stereotyped behavior groups also differed significantly with respect to their ABC irritability and hyperactivity scores, and that participants in the BPI self-injurious behavior groups differed significantly with respect to their ABC irritability, lethargy and hyperactivity scores. Thus, although the results of these MANCOVA analyses in the current study gives additional support for the convergent validity of some of the BPI and ABC subscales, they do not fully support the results found by Rojahn et al. (2003). These discrepancies in the results of the two studies could be a function of: (i) the methodological differences between the analyses undertaken in the current study and the analyses undertaken in Rojahn et al.’s (2003) study and/or (ii) the differing severities of behavioral disturbance in the participants of each study. In addition to the categorical group comparisons, Rojahn et al. (2003) conducted linear regression analyses to examine which of the three BPI subscales significantly predicted the five ABC subscales. The findings were that the BPI aggressive/destructive behavior subscale significantly predicted the ABC irritability subscale, the BPI stereotyped behavior subscale significantly predicted the ABC stereotypy and lethargy subscales, and the BPI self-injurious behavior subscale significantly predicted the ABC irritability, lethargy, stereotypy and hyperactivity subscales. The current study replicated these analyses and found that the BPI aggressive/destructive behavior subscale significantly predicted the ABC irritability, stereotypy and hyperactivity subscales, and the BPI stereotyped behavior subscale significantly predicted the ABC stereotypy and lethargy subscales. The BPI self-injurious behavior subscale however did not predict any of the ABC subscales. Some of these results are consistent with those obtained by Rojahn et al. (2003) but there are also some discrepancies. Both the current study and Rojahn et al.’s (2003) study found that the BPI stereotyped behavior subscale significantly predicted the ABC stereotypy and lethargy subscales, and that the BPI aggressive/destructive behavior subscale significantly predicted the ABC irritability subscale. The current study additionally found that the BPI aggressive/destructive behavior subscale significantly predicted the ABC stereotypy and hyperactivity subscales. Rojahn et al. (2003), on the other hand, additionally found that the BPI self-injurious behavior subscale significantly predicted the ABC irritability, lethargy, stereotypy and hyperactivity subscales (the BPI self-injurious behavior subscale did not predict any of the ABC subscales in the current study). These findings can be better understood by examining the items contained in the BPI and ABC subscales. Overall, strong evidence for convergent validity between the BPI and the ABC was found. Initially, a strong positive correlation was noted between BPI total scores and ABC total scores suggesting that there may be a relationship between the two assessments. A strong positive correlation was also found between the BPI stereotyped behavior subscale and the ABC stereotypy subscale, suggesting that there may be a relationship between these two subscales. MANCOVA analyses confirmed that there was indeed a relationship between BPI stereotyped behavior subscale scores and ABC stereotypy subscale scores, and multiple regression analyses indicated that the BPI stereotyped behavior subscale significantly predicted the ABC stereotypy subscale. As 36% of the variance in the ABC stereotypy subscale was explained by the BPI stereotyped behavior and aggressive/destructive behavior subscales, this can be seen as strong evidence of convergent validity. These results are in keeping with the overlap in the items contained within each of the subscales, i.e. both of the subscales contain items relating to: (i) moving/rolling the head back and forth, (ii) moving the hands, head and/or body in a repetitive manner and (iii) body rocking. A strong positive correlation was also found between the BPI
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stereotyped behavior subscale and the ABC lethargy subscale suggesting that there may be a relationship between these two subscales. MANCOVA analyses confirmed that there was indeed a relationship between BPI stereotyped behavior subscale scores and ABC lethargy subscale scores, and multiple regression analyses indicated that the BPI stereotyped behavior subscale significantly predicted the ABC lethargy subscale. The ABC lethargy subscale includes items such as: (i) is withdrawn, prefers solitary activities, (ii) is unresponsive to structured activities and (iii) is difficult to reach, contact or get through to. All of these behaviors are likely to be associated with individuals who spend a large amount of their time engaging in stereotyped behavior and thus it is clear why the analyses performed found an association between the two subscales. However, as only 7% of the variance in the ABC lethargy subscale was explained by the BPI stereotyped behavior subscale, it is also clear that these subscales additionally identify different sorts of problem behaviors. For example, the ABC lethargy subscale includes items such as: (i) does nothing but sit and watch others, (ii) sits or stands in one position for a long time, (iii) does not try to communicate by words or gestures and (iv) is inactive, never moves spontaneously. Similar arguments may be adduced to explain the negative relationship between the BPI aggressive/destructive behavior subscale and the ABC stereotypy subscale and the patterns of findings concerning the BPI aggressive/destructive behavior subscale and the ABC hyperactivity subscale, and the BPI aggressive/destructive behavior subscale and the ABC irritability subscale. For example, the ABC irritability subscale items: (i) is aggressive to other children or adults (verbally or physically), (ii) stamps feet, bangs objects or slams doors and (iii) screams inappropriately, are very similar to several of the BPI aggressive/destructive behavior subscale items, including: (i) hitting others, (ii) being verbally abusive with others and (iii) destroying things. However, only 10% of the variance in the ABC irritability subscale was explained by the BPI aggressive/destructive behavior subscale, thus it is clear that these subscales also identify different sorts of problem behaviors. For example, the ABC irritability subscale includes items relating to self-injurious behavior, i.e. (i) injures self on purpose and (ii) deliberately hurts himself/herself, whereas the BPI aggressive destructive behavior subscale does not (items relating to self-injurious behavior are included in the BPI self-injurious behavior subscale). Meaningful relationships between scores on BPI and ABC subscales would, of course, only be expected if subscale scores for both instruments were themselves psychologically meaningful. The ABC, as noted in Section 1, has repeatedly been found to have a factor structure consistent with its subscale structure, but research on the initial version of the BPI produced more mixed results, with Sturmey et al. (1993) finding factors corresponding to the aggressive/ destructive behavior and self-injurious behavior, but not the stereotyped behavior, subscales and Sturmey et al. (1995), finding neither a factor corresponding to the aggressive/destructive behavior nor the stereotyped behavior subscales. By contrast, the present study identified a factor clearly corresponding to the aggressive/destructive behavior subscale, two corresponding respectively to fine and gross motor stereotyped behavior, one related to stereotyped whirling and spinning, one related to stereotyped sniffing and rubbing of own body and objects and one related to self-injury. Our findings therefore suggest that when used to assess people with severe behavior problems, the factor structure of the BPI is substantially congruent with its subscale structure. In summary, the current study found a significant relationship between overall BPI and ABC scores and between some of the BPI and ABC subscales. Additionally, the current study found that some of the BPI subscales were able to significantly predict some of the ABC subscales. Thus, consistent with the results of Rojahn et al. (2003), the current study found that the two
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rating scales cross-validated each other in a convergent and divergent manner when utilised to assess individuals presenting with multiple complex behavior problems. The main strength of the current study was that it replicated and extended Rojahn et al.’s (2003) study in demonstrating convergent validity for the BPI and the ABC when used to assess individuals presenting with multiple complex behavior problems. Thus, while Rojahn et al.’s (2003) study included many participants with BPI scores of 0 (indicating low levels of behavioral disturbance), the lowest obtained BPI score in the current study was 10 (indicating much higher levels of behavioral disturbance). Another major strength of the current study was that it demonstrated that the factor structure of the BPI is substantially congruent with its subscale structure, when used to assess people with severe behavior problems. However, a weakness of these factor analyses is that they were conducted on only 76 participants, which is lower than would normally be desired for this type of analysis. References Aman, M. G., Burrow, W. H., & Wolford, P. L. (1995). The aberrant behavior checklist—community: Factor validity and effect of subject variables for adults in group homes. American Journal on Mental Retardation, 100, 283–292. Aman, M. G., & Singh, N. N. (1986). Aberrant behavior checklist: Manual. East Aurora, NY: Slosson Educational Publications. Aman, M. G., Singh, N. N., Stewart, A. W., & Field, C. J. (1985). Psychometric characteristics of the aberrant behavior checklist. American Journal of Mental Deficiency, 89, 492–502. Aman, M. G., Singh, N. N., & Turbott, S. H. (1987). Reliability of the aberrant behavior checklist and the effect of variations in instructions. American Journal of Mental Deficiency, 92, 237–240. Bihm, E., & Poindexter, A. R. (1991). Cross-validation of the factor structure of the aberrant behavior checklist for persons with mental retardation. American Journal on Mental Retardation, 96, 209–211. Brown, E. C., Aman, M. G., & Havercamp, S. M. (2002). Factor analysis and norms for parent ratings on the aberrant behavior checklist—community for young people in special education. Research in Developmental Disabilities, 23, 45–60. Lambert, N., Nihira, K., & Leland, H. (1993). AAMR adaptive behavior scale—school: Examiner’s manual (2nd ed.). New York: Slosson Educational Publications. Marshburn, E. C., & Aman, M. G. (1992). Factor validity and norms for the aberrant behavior checklist in a community sample of children with mental retardation. Journal of Autism and Developmental Disorders, 22, 357–373. Matson, J. L. (1995). The diagnostic assessment for the severely handicapped—Revised (DASH-II). Baton Rouge, LA: Scientific Publishers. McGrew, K. S., Ittenbach, R. F., Bruininks, R. H., & Hill, B. K. (1991). Factor structure of maladaptive behaviours across the lifespan of persons with mental retardation. Research in Developmental Disabilities, 12, 181–199. Nihira, K., Leland, H., & Lambert, N. (1993). AAMR adaptive behavior scale—residential and community: Examiner’s manual (2nd ed.). New York: Slosson Educational Publications. Rojahn, J. (1984). Self-injurious behaviour in institutionalised, severely/profoundly retarded adults: Prevalence data and staff agreement. Journal of Behavioral Assessment, 6, 13–27. Rojahn, J. (1986). Self-injurious behaviour and stereotypic behaviour of non-institutionalised mentally retarded people: Prevalence and classification. American Journal of Mental Deficiency, 91, 268–276. Rojahn, J., Aman, M. G., Matson, J. L., & Mayville, E. (2003). The aberrant behavior checklist and the behavior problems inventory: Convergent and divergent validity. Research in Developmental Disabilities, 24, 391–404. Rojahn, J., & Helsel, W. J. (1991). The aberrant behavior checklist with children and adolescents with dual diagnosis. Journal of Autism and Developmental Disorders, 21, 17–28. Rojahn, J., Matson, J. L., Lott, D., Esbensen, A. J., & Smalls, Y. (2001). The behavior problems inventory: An instrument for the assessment of self-injury, stereotyped behavior and aggression/destruction in individuals with developmental disabilities. Journal of Autism and Developmental Disorders, 31, 577–588. Rojahn, J., Matlock, S. T., & Tasse´, M. J. (2000). The stereotyped behavior scale: Psychometric properties and norms. Research in Developmental Disabilities, 21, 437–454. Rojahn, J., Polster, L. M., & Mulick, J. A. (1989). Reliability of the behavior problems inventory. Journal of the Multihandicapped Person, 2, 283–293.
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Rojahn, J., Tasse´, M. J., & Sturmey, P. (1997). The stereotyped behavior scale for adolescents and adults with mental retardation. American Journal on Mental Retardation, 102, 137–146. Sturmey, P., Fink, C., & Sevin, J. (1993). The behavior problems inventory: A replication and extension of its psychometric properties. Journal of Developmental and Physical Disabilities, 5, 327–336. Sturmey, P., Sevin, J., & Williams, D. E. (1995). The behavior problems inventory: A further replication of its factor structure. Journal of Intellectual Disability Research, 39, 353–356.
Convergent validity of the aberrant behavior checklist and behavior problems inventory with people with complex needs§ Jennie Hill a, Stephanie Powlitch b, Frederick Furniss c,d,* a
Nottinghamshire Healthcare NHS Trust, Rampton Hospital, Retford, UK b Norwich Primary Care NHS Trust, Norwich, UK c The Hesley Group, Doncaster, UK d School of Psychology, University of Leicester, UK Received 3 October 2006; accepted 10 October 2006
Abstract The current study aimed to replicate and extend Rojahn et al. [Rojahn, J., Aman, M. G., Matson, J. L., & Mayville, E. (2003). The aberrant behavior checklist and the behavior problems inventory: Convergent and divergent validity. Research in Developmental Disabilities, 24, 391–404] by examining the convergent validity of the behavior problems inventory (BPI) and the aberrant behavior checklist (ABC) for individuals presenting with multiple complex behavior problems. Data were collected from 69 children and adults with severe intellectual disabilities and challenging behavior living in residential establishments. MANCOVA analyses showed that individuals with elevated BPI stereotyped behavior subscale scores had higher scores on ABC lethargy and stereotypy subscales, while those with elevated BPI aggressive/destructive behavior subscale scores obtained higher scores on ABC irritability, stereotypy and hyperactivity subscales. Multiple regression analyses showed a corresponding pattern of results in the prediction of ABC subscale scores by BPI subscale scores. Exploratory factor analysis of the BPI data suggested a six-factor solution with an aggressive/destructive behavior factor, four factors relating to stereotypy, and one related to stereotypy and self-injury. These results, discussed with reference to Rojahn et al. [Rojahn, J., Aman, M. G., Matson, J. L., & Mayville, E. (2003). The aberrant behavior checklist and the behavior problems inventory: Convergent and divergent validity. Research in Developmental Disabilities, 24, 391–404], support the existence of relationships between specific subscales of the two instruments in
§ A preliminary version of this paper was presented to the 2004 World Congress of the International Association for the Scientific Study of Intellectual Disability. * Corresponding author at: The Hesley Group, Mallard House, Sidings Court, Doncaster DN4 5NU, UK. Tel.: +44 1302 386900; fax: +44 1302 386901. E-mail address: [email protected] (F. Furniss).
0891-4222/$ – see front matter # 2006 Elsevier Ltd. All rights reserved. doi:10.1016/j.ridd.2006.10.002
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addition to an overall association between total scores related to general severity of behavioral disturbance. # 2006 Elsevier Ltd. All rights reserved. Keywords: Aberrant behavior checklist; Assessment; Problem behavior; Behavior problems inventory; Validity
1. Introduction Several instruments currently exist for assessing behavioral disorders in individuals with severe intellectual disabilities. These instruments are widely used as screening tools for detecting potential challenging behaviors, developing and evaluating intervention strategies, and clinical research. One reason challenging behaviors such as aggressive outbursts, stereotyped behaviors and self-injury routinely need to be assessed in individuals with severe intellectual disabilities is because they can impede successful integration into the community (Rojahn, Aman, Matson, & Mayville, 2003). Current behavioral assessment scales can be distinguished into two categories by their scope. Generalised behavior rating scales assess a number of different conditions, each of which consists of a number of sub-conditions. For example, psychopathology is a condition that consists of sub-conditions such as mania, mood disorders and anxiety. Although generalised rating scales encompass extensive ranges of psychopathology, they are typically restricted to relatively few items per clinical condition and thus can be potentially unreliable (Rojahn, Matson, Lott, Esbensen, & Smalls, 2001). Specialised behavior rating scales on the other hand assess only narrowly defined conditions, such as aggression. The aberrant behavior checklist (ABC) (Aman & Singh, 1986) is a generalised behavior rating scale which was developed inductively, i.e. the subscales included in the ABC (irritability, lethargy, stereotypy, hyperactivity and inappropriate speech) were developed by factor analysing reports of clinically observed behaviors. A number of psychometric studies have subsequently confirmed the factor validity of the ABC in a variety of population groups (Aman, Burrow, & Wolford, 1995; Bihm & Poindexter, 1991; Marshburn & Aman, 1992), although Brown, Aman, and Havercamp (2002) found a four-factor model lacking an ‘‘inappropriate speech’’ factor in a population of children and adolescents in special education settings. A number of studies have found the criterion validity of the ABC to range from adequate to very good (Aman, Singh, Stewart, & Field, 1985; Rojahn & Helsel, 1991). The ABC has also been found to be reliable. For example, Aman et al. (1985) found the ABC to have very good internal consistency (coefficient alphas ranged from 0.86 to 0.94 across subscales), acceptable interrater reliability (mean Spearman correlation coefficients across pairs of raters ranged from 0.55 to 0.69 across subscales) and very good test–retest reliability (Spearman correlation coefficients between pairs of scores given by raters 4 weeks apart ranged from 0.96 to 0.99 across subscales). Aman, Singh, and Turbott (1987), using Pearson correlations to assess agreement, found generally comparable levels of inter-rater reliability but lower, although still very acceptable, test–retest reliability. The behavior problems inventory (BPI) (Rojahn et al., 2001) is a specialised behavior rating scale. Item selection for the subscales of the BPI was achieved by a literature review of studies assessing problem behavior instruments. The BPI was originally a 32-item rating scale containing only items relating to self-injurious behavior and stereotypies (Rojahn, 1984, 1986) but has been developed over the years, including the addition of a social maladaptation dimension
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to the scale (McGrew, Ittenbach, Bruininks, & Hill, 1991) and the replacement of the original stereotypies subscale with the independently developed ‘‘stereotyped behavior scale’’ (Rojahn, Matlock, & Tasse´, 2000; Rojahn, Tasse´, & Sturmey, 1997). Sturmey, Sevin, and Williams (1995) found the BPI to have good test–retest and inter-rater reliability, although variable levels of reliability across items and subscales had previously been found by the original author (Rojahn, Polster, & Mulick, 1989). Internal and criterion-related validity levels for the BPI have been found to be modest to good (Rojahn et al., 2001). Factor analysis of the BPI on the other hand has yielded varied results. Sturmey, Fink, and Sevin (1993) used principal components factor analysis which yielded a two-factor structure. These two factors closely resembled the BPI aggression and self-injury subscales, but no factor corresponding to the stereotypy subscale was found. In a replication study, Sturmey et al. (1995) proposed a two- or three-factor structure. In this study, the factors yielded contained only items relating to self-injury, thus neither an aggression factor nor a stereotypy factor was found. These studies also found the self-injury subscale to be multi-factorial, suggesting that self-injury items do not form a single dimension (Sturmey et al., 1993, 1995). However, all of these factor analyses were conducted on the original BPI (Rojahn, 1984, 1986), not the revised one (Rojahn et al., 2001). Rojahn et al. (2001) performed a confirmatory factor analysis on data from 432 individuals with intellectual disabilities, assuming 3 oblique factors corresponding to the BPI subscales, and found mean factor loadings of 0.34 for the SIB, 0.38 for the stereotyped behavior, and 0.54 for the aggression/ destruction subscales. To date, however, no exploratory factor analysis appears to have been published on the current BPI. Previous research (Rojahn et al., 2003) has demonstrated selective relationships between subscale scores on the BPI and the ABC, supporting the convergent validity of the scales. This research however included many participants with BPI scores of 0, indicating low levels of behavioral disturbance in these individuals. The aims of the present study were thus: (1) to examine the convergent validity of the BPI and the ABC when used to assess individuals presenting with multiple complex behavior problems and (2) in view of the variability in previous findings concerning the factor structure of the BPI, to conduct a factor analysis using principal components analysis to investigate the factor structure of the current BPI when used with this population group. 2. Method 2.1. Participants Participants were 69 children and adults (58 males and 11 females) with severe intellectual disabilities and challenging behavior living in one of four residential establishments in England. The mean age of the participants was 18 years and 5 months (minimum 9 years and 4 months— maximum 29 years and 7 months). Each participant was assessed using either the AAMR adaptive behavior scale—school (Lambert, Nihira, & Leland, 1993) or the AAMR adaptive behavior scale—residential (Nihira, Leland, & Lambert, 1993), dependent upon whether they were below or above 18 years of age respectively, to assess their adaptive abilities. The mean independent functioning standard score of the participants was 9 (minimum 1—maximum 12) and the mean language development standard score of the participants was 7 (minimum 2— maximum 13). Scores from routine assessments using the Diagnostic Assessment for the Severely Handicapped II (DASH-II) (Matson, 1995) were available for 49 participants. Mean DASH-II PDD/Autism subscale score for participants was 7 (range 2–12).
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Data for seven additional participants (five males and two females) for whom BPI, but not ABC, data were available were used in factor analysis of BPI items. The mean age of the additional participants was 16 years 11 months, the mean independent functioning standard score of the four additional participants for whom scores were available was 9, and their mean language development score was 8. 2.2. Instruments 2.2.1. The behavior problems inventory (BPI) The BPI is a 52-item specialised (Rojahn et al., 2003) behavior rating scale designed to assess specific problem behaviors in individuals with intellectual and developmental disabilities. The BPI used in the present study was the BPI-01 edition, described by Rojahn et al. (2001). The three subscales of the BPI-01 are: (i) self-injurious behavior (14 items), (ii) stereotyped behavior (24 items) and (iii) aggressive/destructive behavior (11 items). Each subscale also has a residual item, so that respondents can include any behavior not included in the list of items that meets the definition of the targeted problem behavior (e.g. ‘‘other stereotypy’’). Each subscale item is scored on two scales: (a) a frequency scale ranging from never: 0, through to hourly: 4 (5-point scale) and (b) a severity scale ranging from no problem: 0, through to severe problem: 3 (4-point scale). The behavior must have appeared at least once over the past 2 months in order for it to be rated (i.e. given a frequency score greater than 0). 2.2.2. The aberrant behavior checklist (ABC) The ABC (Aman & Singh, 1986) is a factor analytically derived 58-item generalised behavior rating scale. The ABC was originally designed to aid in the evaluation of psychotropic drug treatments for individuals with severe and profound intellectual and developmental disabilities, although it can also be used as a general assessment tool for problem behaviors. The five subscales of the ABC are: (i) irritability (15 items), (ii) lethargy (16 items), (iii) stereotypy (7 items), (iv) hyperactivity (16 items) and (v) inappropriate speech (4 items). Each subscale item is scored on a severity scale ranging from not at all a problem: 0, through to the problem is severe in degree: 3 (4-point scale). The behavior must have appeared at least once over the past 4 weeks in order for it to be rated (i.e. given a severity score greater than 0). 2.3. Interviewers and respondents Either a clinical psychologist or a psychology graduate administered the BPI. Psychology graduates administered the ABC. The respondents were the direct support staff members who had worked with each participant the longest. 3. Results Data analysis was performed on both the total scores and the subscales for each instrument. As with Rojahn et al.’s (2003) study, high (Pearson) correlations were found between the frequency and severity scales of the BPI (0.88 for self-injurious behavior, 0.92 for stereotyped behavior and 0.80 for aggressive/destructive behavior, n = 69). For this reason, only the frequency scales of the BPI were used in further analyses. Table 1 shows the means, standard deviations, minima and maxima of the ABC and BPI total and subscale scores. Neither the ABC nor the BPI had normally distributed data. However, this feature is characteristic of maladaptive behavior data. In
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Table 1 Means, standard deviations, minima and maxima for BPI and ABC scores (n = 69) Mean
S.D.
Minimum
Maximum
BPI Total score
46.19
21.07
10
109
Subscales Self-injurious behavior Stereotyped behavior Aggressive/destructive behavior
8.29 26.20 11.70
5.45 16.47 8.35
0 0 0
26 80 38
ABC Total score
51.83
22.12
6
100
Subscales Irritability Lethargy Stereotypy Hyperactivity Inappropriate speech
16.46 10.68 4.91 16.42 3.35
8.73 7.23 4.02 9.37 3.70
0 0 0 2 0
40 33 15 36 12
general, these data sets have positive skewness and kurtosis (Rojahn et al., 2003). This pattern was found in the present data set for BPI total scores (skewness of 0.71 and kurtosis of 0.52) but not for the ABC total scores (skewness of 0.11 and kurtosis of 0.77). 3.1. Preliminary correlations The first set of analyses obtained Pearson correlations between the BPI total and subscale scores and ABC total and subscale scores (see Table 2). Significant positive correlations were found between total BPI score and total ABC score, between total BPI score and ABC irritability, lethargy, stereotypy and hyperactivity subscale scores, between total ABC score and BPI stereotyped behavior subscale score, BPI self-injurious behavior subscale score and ABC irritability subscale score, BPI stereotyped behavior subscale score and ABC stereotypy and lethargy subscale scores, and BPI aggressive/destructive behavior subscale score and ABC irritability and hyperactivity subscale scores. A significant negative correlation was found between BPI aggressive/destructive behavior subscale score and ABC stereotypy subscale score. Significant correlations were not found between any other BPI and ABC subscale scores. Table 2 Pearson correlations between BPI and ABC subscale and total scores BPI total score ABC ABC ABC ABC ABC ABC a b
total score irritability lethargy stereotypy hyperactivity inappropriate speech
0.37a 0.27b 0.29b 0.36a 0.26b 0.07
BPI self-injurious behavior 0.22 0.29b 0.19 0.13 0.04 0.04
Correlation is significant at the 0.01 level (two-tailed). Correlation is significant at the 0.05 level (two-tailed).
BPI stereotyped behavior 0.29b 0.09 0.31b 0.55a 0.18 0.13
BPI aggressive/ destructive behavior 0.22 0.32a 0.02 0.26b 0.29b 0.06
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3.2. Categorical or group comparisons These analyses were ‘designed to test the hypothesis that individuals with elevated BPI subscale scores should have higher scores on some ABC subscale scores, as compared to individuals with low BPI scores’ (Rojahn et al., 2003, p. 395). Two sets of analyses were performed. For the first set of analyses, the sample was divided into two groups: a ‘‘moderate behavior disturbance’’ group containing participants who had no items with a score of 4 on either the BPI self-injurious behavior subscale or the BPI aggressive/destructive behavior subscale (n = 49) and a ‘‘severe behavior disturbance’’ group containing participants who had at least one item with a score of 4 on either the BPI self-injurious behavior subscale or the BPI aggressive/ destructive behavior subscale (n = 20). Fig. 1 displays the ABC mean subscale scores for these two groups. A MANOVA conducted with the ABC subscale scores as the dependent variables yielded a non-significant multivariate effect (Wilks’ l = 0.97, p = 0.87). None of the ABC subscales showed significant group differences. In the second set of analyses, ‘the unique effect of each of the three BPI subscale scores on the ABC subscale scores was determined, while controlling for the variance of the two other BPI subscales’ (Rojahn et al., 2003, p. 395). Three MANCOVAs were computed, one for each subscale: (i) The BPI self-injurious behavior (SIB) dichotomous subscale score (group 1: SIB score < SIB mean score, n = 39; group 2: SIB score > SIB mean score, n = 30) was the grouping variable, the ABC subscale scores were the dependent variables and the BPI
Fig. 1. Mean ABC subscale scores for ‘‘moderate behavior disturbance’’ group (participants with no items with a score of 4 on either the BPI self-injurious behavior subscale or the BPI aggression/destruction subscale) and ‘‘severe behavior disturbance’’ group (participants with at least one item with a score of 4 on either the BPI self-injurious behavior subscale or the BPI aggression/destruction subscale).
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Table 3 Summary table of MANCOVA results Tests MANCOVA: SIB < SIB mean vs. SIB > SIB mean Multivariate: Wilks’ l = 0.93, between-subjects ABC irritability ABC lethargy ABC stereotypy ABC hyperactivity ABC inappropriate speech MANCOVA: STER < STER mean vs. STER > STER mean Multivariate: Wilks’ l = 0.70, between-subjects ABC irritability ABC lethargy ABC stereotypy ABC hyperactivity ABC inappropriate speech
F
d.f.
Significance
0.97 0.16 0.13 0.88 2.23 0.09
5/61 1/65 1/65 1/65 1/65 1/65
0.44 0.70 0.72 0.35 0.14 0.76
5.14 0.01 6.73 19.12 0.91 1.59
5/61 1/65 1/65 1/65 1/65 1/65
0.001 0.92 0.01 0.001 0.34 0.21
5/61 1/65 1/65 1/65 1/65 1/65
0.001 0.02 0.30 0.05 0.01 0.44
MANCOVA: AGG/DES < AGG/DES mean vs. AGG/DES > AGG/DES mean Multivariate: Wilks’ l = 0.72, between-subjects 4.84 ABC irritability 6.25 ABC lethargy 1.12 ABC stereotypy 4.11 ABC hyperactivity 8.61 ABC inappropriate speech 0.61
SIB, BPI self-injurious behavior subscale score; STER, BPI stereotyped behavior subscale score; AGG/DES, BPI aggressive/destructive behavior subscale score.
stereotyped behavior and aggressive/destructive behavior subscale scores were the covariates. The overall multivariate effect was found to be non-significant (Wilks’ l = 0.93, p = 0.44) and participants in these SIB groups did not differ with regard to any of the ABC subscale scores (Table 3, first panel). (ii) The BPI stereotyped behavior (STER) dichotomous subscale score (group 1: STER score < STER mean score, n = 35; group 2: STER score > STER mean score, n = 34) was the grouping variable, the ABC subscale scores were the dependent variables and the BPI self-injurious behavior and aggressive/destructive behavior subscale scores were the covariates. The overall multivariate effect was found to be significant (Wilks’ l = 0.70, p = 0.001) as were the effects for the ABC lethargy and stereotypy subscales. Participants in these STER groups did not differ with regard to their ABC irritability, hyperactivity and inappropriate speech subscales scores (Table 3, second panel). (iii) The BPI aggressive/destructive behavior (AGG/DES) dichotomous subscale score (group 1: AGG/DES score < AGG/DES mean score, n = 40; group 2: AGG/DES score > AGG/ DES mean score, n = 29) was the grouping variable, the ABC subscale scores were the dependent variables and the BPI self-injurious behavior and stereotyped behavior subscale scores were the covariates. The overall multivariate effect was found to be significant (Wilks’ l = 0.72, p = 0.001) as were the effects for the ABC irritability, stereotypy and hyperactivity subscales. Participants in these AGG/DES groups did not differ with regard to their ABC lethargy and inappropriate speech subscales scores (Table 3, third panel).
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3.3. Multiple regression Five multiple regression analyses were conducted to assess whether any of the five ABC subscales would be significantly predicted by any of the three BPI subscales. The BPI subscales were the independent variables and the ABC subscales were the dependent variables. Table 4 summarises the results of these analyses. The first regression equation, with the ABC irritability subscale as the dependent variable, was significant (F = 3.48, d.f. = 3, 65, p < 0.05). This equation was able to explain 10% of the variance in ABC irritability subscale score. However, inspection of the beta weights reveals that only the BPI aggressive/destructive behavior subscale made a significant contribution to the prediction of the ABC irritability subscale. The second regression equation, with the ABC lethargy subscale as the dependent variable, was significant (F = 2.75, d.f. = 3, 65, p = 0.05). This equation was able to explain 7% of the variance in ABC lethargy subscale score. Inspection of the beta weights reveals that only the BPI stereotyped behavior subscale made a significant contribution to the prediction of the ABC lethargy subscale. The third multiple regression equation, with the ABC stereotypy subscale as the dependent variable, was highly significant (F = 13.96, d.f. = 3, 65, p < 0.001). This equation was able to explain 36% of the variance in the ABC stereotypy subscale score. Inspection of the beta weights reveals that both the BPI stereotyped behavior and the BPI aggressive/destructive behavior subscales made significant contributions to the prediction of the ABC stereotypy subscale. The fourth regression equation, with the ABC hyperactivity subscale as the dependent variable, was also significant (F = 3.00, d.f. = 3, 65, p < 0.05). However, this equation was only able to explain 8% of the variance in the ABC hyperactivity subscale score. Inspection of the beta weights reveals that only the BPI aggressive/destructive behavior subscale made a significant
Table 4 Prediction of ABC subscale scores by BPI subscales: multiple regression analyses R2 adjusted
BPI subscale
b
ABC irritability
0.10
*
Self-injurious behavior Stereotyped behavior Aggressive/destructive behavior
0.19 0.04 0.25*
ABC lethargy
0.07*
Self-injurious behavior Stereotyped behavior Aggressive/destructive behavior
0.15 0.28* 0.04
ABC stereotypy
0.36***
Self-injurious behavior Stereotyped behavior Aggressive/destructive behavior
0.14 0.53*** 0.32**
ABC hyperactivity
0.08*
Self-injurious behavior Stereotyped behavior Aggressive/destructive behavior
0.11 0.19 0.32*
ABC inappropriate speech
0.02
Self-injurious behavior Stereotyped behavior Aggressive/destructive behavior
0.05 0.14 0.05
* ** ***
p < 0.05. p < 0.01. p < 0.001.
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contribution to the prediction of the ABC hyperactivity subscale. The fifth and final regression equation, with the ABC inappropriate speech subscale as the dependent variable, was not significant (F = 0.52, d.f. = 3, 65, p = 0.67). In summary, the BPI stereotyped behavior subscale significantly predicted both the ABC lethargy subscale and the ABC stereotypy subscale. The BPI aggressive/destructive behavior subscale significantly predicted the ABC irritability subscale, the ABC stereotypy subscale and the ABC hyperactivity subscale. The BPI self-injurious behavior subscale however did not predict any of the ABC subscales.
Table 5 Factor analysis of all BPI items with loadings of items on to factors BPI item (and subscale)
Factor I
41. Hitting others (AGG/DES) 45. Grabbing/pulling others (AGG/DES) 42. Kicking others (AGG/DES) 43. Pushing others (AGG/DES) 46. Scratching others (AGG/DES) 51. Being mean or cruel (AGG/DES) 48. Spitting on others (AGG/DES) 47. Pinching others (AGG/DES) 44. Biting others (AGG/DES) 26. Yelling/screaming (STER) 50. Destroying things (AGG/DES) 31. Complex hand movements (STER) 33. Sustained finger movements (STER) 25. Repetitive hand movements (STER) 22. Repetitive body movements (STER) 39. Waving hands (STER) 20. Rolling head (STER) 19. Waving or shaking arms (STER) 37 Clapping hands (STER) 28. Bouncing around (STER) 16. Rocking back & forth (STER) 30. Bursts of running around (STER) 23. Pacing (STER) 24. Twirling things (STER) 34. Rubbing self (STER) 21. Whirling, turning on spot (STER) 18. Spinning own body (STER) 9 Pulling finger or toe nails (SIB) 39 Waving hands (STER) 4. Self-scratching (SIB) 6. Self-pinching (SIB) 12. Hair pulling (SIB) 13. Extreme drinking (SIB) 27. Sniffing own body (STER) 17. Sniffing objects (STER) 10. Inserting fingers into body openings (SIB)
0.837 0.771 0.737 0.736 0.697 0.662 0.637 0.525 0.459 0.382 0.346
II
III
IV
V
VI
0.321
0.327 0.809 0.807 0.781 0.650 0.532 0.434 0.404
0.338
0.343
0.461 0.753 0.711 0.619 0.618 0.477 0.439 0.349
0.359 0.836 0.836 0.374 0.352 0.851 0.775 0.557 0.432 0.810 0.783 0.453
SIB, BPI self-injurious behavior subscale; STER, BPI stereotyped behavior subscale score; AGG/DES, BPI aggressive/ destructive behavior subscale score.
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3.4. Factor analysis of BPI data In view of the limited amount of information available on the factor structure of the BPI, an exploratory factor analysis was undertaken. As noted above, this analysis used BPI data from 76 participants. Principal components analysis with varimax rotation was used as this method had been used in previous analyses of the factor structure of the original BPI. Fifteen factors with initial eigenvalues exceeding 1 were identified, of which the first six had eigenvalues exceeding 2 and were readily interpretable; these six accounting for 10, 7.8, 6.2, 5.2, 5.2 and 4.8% of the variance, respectively. Table 5 lists the items with a factor loading of 0.3. All but one of the items from the BPI aggressive/destructive behavior subscale loaded on to the first factor identified. Factors II, III, IV and VI received loadings predominantly from the stereotyped behavior subscale of the BPI, with factor II mainly relating to fine motor stereotypies, factor III to overactivity/gross motor stereotypy, factor IV to whirling/ spinning and factor VI to sniffing and rubbing. Factor V predominantly received loadings from items relating to scratching, pinching and hair-pulling from the self-injurious behavior subscale. A further analysis, again using principal components analysis with varimax rotation, was carried out on items from the self-injurious behavior subscale alone. Five factors with eigenvalues exceeding 1 were identified, with eigenvalues of 3.11, 1.85, 1.46, 1.25 and 1.09, respectively, and accounting for 20.6, 11.9, 11.6, 9.8 and 8.6% of the variance. Table 6 presents the pattern of factor loadings of 0.3. Factor I related to self-biting, scratching, pinching, hair-pulling and self-hitting; factor II to inappropriate placing of fingers and objects in body cavities (including pica), teeth grinding, self-scratching (negatively) and selfhitting; factor III related to vomiting/regurgitation and inappropriate placing of objects/ materials in body cavities (including pica). The remaining two factors each received substantial loadings from two items only, in the case of factor IV air-swallowing and excessive drinking, and in the case of factor 5 pulling nails and inserting fingers into body openings.
Table 6 Factor analysis of BPI self-injurious behavior subscale items with loadings of items on to factors BPI self-injurious behavior subscale item
Factor I
6. Self-pinching 12. Hair pulling 2. Hitting head with hand/body 4. Self-scratching 1. Self-biting 3. Hitting body with hand/body 7. Pica, mouthing or swallowing objects 14. Teeth grinding 10. Inserting fingers into body openings 8. Inserting objects into body openings 5. Vomiting or rumination 11. Air swallowing 13. Extreme drinking 9. Pulling finger or toe nails
0.792 0.703 0.660 0.659 0.650 0.612
II
III
IV
V
0.468 0.342 0.624 0.571 0.442
0.316 0.375 0.507 0.854 0.723 0.823 0.690 0.879
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4. Discussion Previous research has demonstrated selective relationships between subscale scores on the BPI and the ABC in a sample that included many participants with low levels of behavioral disturbance, thus supporting the convergent validity of the scales when conducted on individuals from this population (Rojahn et al., 2003). The current study aimed to replicate Rojahn et al.’s methodology to examine the convergent validity of the BPI and the ABC when used to assess individuals presenting with multiple complex behavior problems. The mean BPI and ABC scores of individuals in the two studies are indicative that participants in the current study presented with significantly higher levels of behavioral disturbance (BPI mean score = 46; ABC mean score = 52) than participants in Rojahn et al.’s (2003) study (BPI mean score = 8; ABC mean score = 12). Rojahn et al. (2003) utilised three sets of analyses to test the hypothesis that individuals with elevated BPI subscale scores should have higher scores on some ABC subscales. Firstly, they split the sample into two sub-groups, (a) BPI total score of 0 and (b) BPI score greater than 0, and compared their ABC subscale scores (using MANOVA). The multivariate test was found to be significant, as were the between-subject tests for the ABC irritability, lethargy, stereotypy and hyperactivity subscales. The two groups were found not to differ significantly in their inappropriate speech scores. These results confirmed that individuals with elevated BPI scores obtained higher ABC subscale scores than individuals with low BPI scores. The current study was not able to replicate this part of Rojahn et al.’s analyses as the lowest obtained BPI score was 10. Correlations between the BPI subscale scores and the ABC subscale scores were thus obtained in the current study to replace Rojahn et al.’s two-group comparison. These correlations indicated: (i) that individuals with elevated BPI scores obtained higher ABC scores and (ii) that individuals with elevated BPI subscale scores obtained higher scores on some of the ABC subscales (significant positive correlations between: (a) BPI self-injurious behavior subscale scores and ABC irritability subscale scores, (b) BPI stereotyped behavior subscale scores and ABC stereotypy subscale scores, (c) BPI stereotyped behavior subscale scores and ABC lethargy subscale scores, (d) BPI aggressive/destructive behavior subscale scores and ABC hyperactivity subscale scores and (e) BPI aggressive/destructive behavior subscale scores and ABC irritability subscale scores). Thus, the results of the correlations in the current study appear to be consistent with the results of the first set of analyses conducted by Rojahn et al. (2003). The second set of analyses utilised by Rojahn et al. (2003) to test the hypothesis that individuals with elevated BPI subscale scores should have higher scores on some ABC subscales involved breaking the sample down into three sub-groups: (a) BPI total score of 0, (b) BPI scores greater than 0, but without a score of 4 on either the self-injurious behavior or the aggressive/ destructive behavior subscales and (c) BPI score greater than 0, with at least one score of 4 on either the self-injurious behavior or the aggressive/destructive behavior subscales. A MANOVA was then conducted to compare their ABC subscale scores. As with the first set of analyses, the multivariate test was found to be significant, as were the between-subject tests for the ABC irritability, lethargy, stereotypy and hyperactivity subscales. The three groups were found not to differ significantly in their inappropriate speech scores. These results again confirmed that individuals with elevated BPI scores have higher ABC subscale scores (except for the inappropriate speech subscale) than individuals with low BPI scores. The current study replicated these analyses as far as possible but, as mentioned previously, it was not possible to create a sub-group of individuals with a BPI score of 0. Thus, a two-group comparison was conducted comparing ABC subscale scores for a moderate behavior disturbance
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group with BPI scores greater than 0, but without a score of 4 on either the self-injurious behavior or the aggressive/destructive behavior subscales, and a severe behavior disturbance group with at least one score of 4 on either the self-injurious behavior or the aggressive/destructive behavior subscales of the BPI. A MANOVA was conducted to compare the two sub-groups’ ABC subscale scores. However, contrary to the findings of Rojahn et al. (2003), the multivariate test in the current study was found to be non-significant and none of the ABC subscales were found to show significant group differences. This discrepancy in findings is likely to be a function of the population groups being examined in each of the studies. The mean ABC subscale scores of the ‘moderate behavior disturbance’ group in the current study were all higher than the corresponding mean ABC subscale scores of the ‘severe behavior disturbance’ group in Rojahn et al.’s (2003) study. This indicates that individuals in the ‘moderate behavior disturbance’ group in the current study were generally more disturbed than the participants in the ‘severe behavior disturbance’ group in Rojahn et al.’s (2003) study. Thus, individuals in the current study received relatively high scores on the ABC subscales regardless of whether or not they received a score of 4 on either the BPI self-injurious behavior or the BPI aggressive/destructive behavior subscales. The third set of analyses utilised by Rojahn et al. (2003) was designed to determine the unique effect of each of the three BPI subscale scores on the ABC subscale scores, while controlling the variance of the other two BPI subscales. In each MANCOVA, the grouping variable was the BPI dichotomous subscale score (group 1: BPI subscale score = 0; group 2: BPI subscale score > 0). In each MANCOVA, the overall multivariate effect was found to be significant. Participants in the BPI self-injurious behavior groups were found to differ significantly with regard to their ABC irritability, lethargy and hyperactivity scores, participants in the BPI stereotyped behavior groups were found to differ significantly with regard to their ABC irritability, lethargy, stereotypy and hyperactivity scores, and participants in the BPI aggressive/destructive behavior groups were found to differ significantly with regard to their irritability, hyperactivity and inappropriate speech scores. These results are indicative that the BPI and the ABC cross-validated each other in a convergent manner when conducted on individuals with low to moderate levels of behavioral disturbance. The current study replicated these analyses, but utilised different group division points when conducting the MANCOVAs (group 1: BPI subscale score < BPI subscale mean score; group 2: BPI subscale score > BPI subscale mean score). This amendment was necessary due to there being very few participants in the current study with BPI subscale scores of 0. The overall multivariate effect was only found to be significant when the BPI stereotyped behavior and the BPI aggressive/destructive behavior dichotomous subscale scores were utilised as the grouping variable, but not when the BPI self-injurious behavior dichotomous subscale score was utilised as the grouping variable. Participants in the BPI stereotyped behavior groups were found to differ significantly with regard to their ABC lethargy and stereotypy scores, and participants in the BPI aggressive/destructive behavior groups were found to differ significantly with regard to their ABC irritability, stereotypy and hyperactivity scores. Participants in the BPI self-injurious behavior groups were not found to differ significantly with regard to any of their ABC subscale scores. Some of these results are consistent with those obtained by Rojahn et al. (2003) but there are also some discrepancies. Both the current study and Rojahn et al.’s (2003) study found that participants in the BPI stereotyped behavior groups differed significantly with respect to their ABC lethargy and stereotypy scores, and that participants in the BPI aggressive/destructive behavior groups differed significantly with respect to their ABC irritability and hyperactivity scores. However, the current study additionally found that participants in the BPI aggressive/ destructive behavior groups differed significantly with respect to their ABC stereotypy scores.
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Conversely, Rojahn et al. (2003) found that participants in the BPI aggressive/destructive behavior groups also differed significantly with respect to their ABC inappropriate speech scores, that participants in the BPI stereotyped behavior groups also differed significantly with respect to their ABC irritability and hyperactivity scores, and that participants in the BPI self-injurious behavior groups differed significantly with respect to their ABC irritability, lethargy and hyperactivity scores. Thus, although the results of these MANCOVA analyses in the current study gives additional support for the convergent validity of some of the BPI and ABC subscales, they do not fully support the results found by Rojahn et al. (2003). These discrepancies in the results of the two studies could be a function of: (i) the methodological differences between the analyses undertaken in the current study and the analyses undertaken in Rojahn et al.’s (2003) study and/or (ii) the differing severities of behavioral disturbance in the participants of each study. In addition to the categorical group comparisons, Rojahn et al. (2003) conducted linear regression analyses to examine which of the three BPI subscales significantly predicted the five ABC subscales. The findings were that the BPI aggressive/destructive behavior subscale significantly predicted the ABC irritability subscale, the BPI stereotyped behavior subscale significantly predicted the ABC stereotypy and lethargy subscales, and the BPI self-injurious behavior subscale significantly predicted the ABC irritability, lethargy, stereotypy and hyperactivity subscales. The current study replicated these analyses and found that the BPI aggressive/destructive behavior subscale significantly predicted the ABC irritability, stereotypy and hyperactivity subscales, and the BPI stereotyped behavior subscale significantly predicted the ABC stereotypy and lethargy subscales. The BPI self-injurious behavior subscale however did not predict any of the ABC subscales. Some of these results are consistent with those obtained by Rojahn et al. (2003) but there are also some discrepancies. Both the current study and Rojahn et al.’s (2003) study found that the BPI stereotyped behavior subscale significantly predicted the ABC stereotypy and lethargy subscales, and that the BPI aggressive/destructive behavior subscale significantly predicted the ABC irritability subscale. The current study additionally found that the BPI aggressive/destructive behavior subscale significantly predicted the ABC stereotypy and hyperactivity subscales. Rojahn et al. (2003), on the other hand, additionally found that the BPI self-injurious behavior subscale significantly predicted the ABC irritability, lethargy, stereotypy and hyperactivity subscales (the BPI self-injurious behavior subscale did not predict any of the ABC subscales in the current study). These findings can be better understood by examining the items contained in the BPI and ABC subscales. Overall, strong evidence for convergent validity between the BPI and the ABC was found. Initially, a strong positive correlation was noted between BPI total scores and ABC total scores suggesting that there may be a relationship between the two assessments. A strong positive correlation was also found between the BPI stereotyped behavior subscale and the ABC stereotypy subscale, suggesting that there may be a relationship between these two subscales. MANCOVA analyses confirmed that there was indeed a relationship between BPI stereotyped behavior subscale scores and ABC stereotypy subscale scores, and multiple regression analyses indicated that the BPI stereotyped behavior subscale significantly predicted the ABC stereotypy subscale. As 36% of the variance in the ABC stereotypy subscale was explained by the BPI stereotyped behavior and aggressive/destructive behavior subscales, this can be seen as strong evidence of convergent validity. These results are in keeping with the overlap in the items contained within each of the subscales, i.e. both of the subscales contain items relating to: (i) moving/rolling the head back and forth, (ii) moving the hands, head and/or body in a repetitive manner and (iii) body rocking. A strong positive correlation was also found between the BPI
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stereotyped behavior subscale and the ABC lethargy subscale suggesting that there may be a relationship between these two subscales. MANCOVA analyses confirmed that there was indeed a relationship between BPI stereotyped behavior subscale scores and ABC lethargy subscale scores, and multiple regression analyses indicated that the BPI stereotyped behavior subscale significantly predicted the ABC lethargy subscale. The ABC lethargy subscale includes items such as: (i) is withdrawn, prefers solitary activities, (ii) is unresponsive to structured activities and (iii) is difficult to reach, contact or get through to. All of these behaviors are likely to be associated with individuals who spend a large amount of their time engaging in stereotyped behavior and thus it is clear why the analyses performed found an association between the two subscales. However, as only 7% of the variance in the ABC lethargy subscale was explained by the BPI stereotyped behavior subscale, it is also clear that these subscales additionally identify different sorts of problem behaviors. For example, the ABC lethargy subscale includes items such as: (i) does nothing but sit and watch others, (ii) sits or stands in one position for a long time, (iii) does not try to communicate by words or gestures and (iv) is inactive, never moves spontaneously. Similar arguments may be adduced to explain the negative relationship between the BPI aggressive/destructive behavior subscale and the ABC stereotypy subscale and the patterns of findings concerning the BPI aggressive/destructive behavior subscale and the ABC hyperactivity subscale, and the BPI aggressive/destructive behavior subscale and the ABC irritability subscale. For example, the ABC irritability subscale items: (i) is aggressive to other children or adults (verbally or physically), (ii) stamps feet, bangs objects or slams doors and (iii) screams inappropriately, are very similar to several of the BPI aggressive/destructive behavior subscale items, including: (i) hitting others, (ii) being verbally abusive with others and (iii) destroying things. However, only 10% of the variance in the ABC irritability subscale was explained by the BPI aggressive/destructive behavior subscale, thus it is clear that these subscales also identify different sorts of problem behaviors. For example, the ABC irritability subscale includes items relating to self-injurious behavior, i.e. (i) injures self on purpose and (ii) deliberately hurts himself/herself, whereas the BPI aggressive destructive behavior subscale does not (items relating to self-injurious behavior are included in the BPI self-injurious behavior subscale). Meaningful relationships between scores on BPI and ABC subscales would, of course, only be expected if subscale scores for both instruments were themselves psychologically meaningful. The ABC, as noted in Section 1, has repeatedly been found to have a factor structure consistent with its subscale structure, but research on the initial version of the BPI produced more mixed results, with Sturmey et al. (1993) finding factors corresponding to the aggressive/ destructive behavior and self-injurious behavior, but not the stereotyped behavior, subscales and Sturmey et al. (1995), finding neither a factor corresponding to the aggressive/destructive behavior nor the stereotyped behavior subscales. By contrast, the present study identified a factor clearly corresponding to the aggressive/destructive behavior subscale, two corresponding respectively to fine and gross motor stereotyped behavior, one related to stereotyped whirling and spinning, one related to stereotyped sniffing and rubbing of own body and objects and one related to self-injury. Our findings therefore suggest that when used to assess people with severe behavior problems, the factor structure of the BPI is substantially congruent with its subscale structure. In summary, the current study found a significant relationship between overall BPI and ABC scores and between some of the BPI and ABC subscales. Additionally, the current study found that some of the BPI subscales were able to significantly predict some of the ABC subscales. Thus, consistent with the results of Rojahn et al. (2003), the current study found that the two
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rating scales cross-validated each other in a convergent and divergent manner when utilised to assess individuals presenting with multiple complex behavior problems. The main strength of the current study was that it replicated and extended Rojahn et al.’s (2003) study in demonstrating convergent validity for the BPI and the ABC when used to assess individuals presenting with multiple complex behavior problems. Thus, while Rojahn et al.’s (2003) study included many participants with BPI scores of 0 (indicating low levels of behavioral disturbance), the lowest obtained BPI score in the current study was 10 (indicating much higher levels of behavioral disturbance). Another major strength of the current study was that it demonstrated that the factor structure of the BPI is substantially congruent with its subscale structure, when used to assess people with severe behavior problems. However, a weakness of these factor analyses is that they were conducted on only 76 participants, which is lower than would normally be desired for this type of analysis. References Aman, M. G., Burrow, W. H., & Wolford, P. L. (1995). The aberrant behavior checklist—community: Factor validity and effect of subject variables for adults in group homes. American Journal on Mental Retardation, 100, 283–292. Aman, M. G., & Singh, N. N. (1986). Aberrant behavior checklist: Manual. East Aurora, NY: Slosson Educational Publications. Aman, M. G., Singh, N. N., Stewart, A. W., & Field, C. J. (1985). Psychometric characteristics of the aberrant behavior checklist. American Journal of Mental Deficiency, 89, 492–502. Aman, M. G., Singh, N. N., & Turbott, S. H. (1987). Reliability of the aberrant behavior checklist and the effect of variations in instructions. American Journal of Mental Deficiency, 92, 237–240. Bihm, E., & Poindexter, A. R. (1991). Cross-validation of the factor structure of the aberrant behavior checklist for persons with mental retardation. American Journal on Mental Retardation, 96, 209–211. Brown, E. C., Aman, M. G., & Havercamp, S. M. (2002). Factor analysis and norms for parent ratings on the aberrant behavior checklist—community for young people in special education. Research in Developmental Disabilities, 23, 45–60. Lambert, N., Nihira, K., & Leland, H. (1993). AAMR adaptive behavior scale—school: Examiner’s manual (2nd ed.). New York: Slosson Educational Publications. Marshburn, E. C., & Aman, M. G. (1992). Factor validity and norms for the aberrant behavior checklist in a community sample of children with mental retardation. Journal of Autism and Developmental Disorders, 22, 357–373. Matson, J. L. (1995). The diagnostic assessment for the severely handicapped—Revised (DASH-II). Baton Rouge, LA: Scientific Publishers. McGrew, K. S., Ittenbach, R. F., Bruininks, R. H., & Hill, B. K. (1991). Factor structure of maladaptive behaviours across the lifespan of persons with mental retardation. Research in Developmental Disabilities, 12, 181–199. Nihira, K., Leland, H., & Lambert, N. (1993). AAMR adaptive behavior scale—residential and community: Examiner’s manual (2nd ed.). New York: Slosson Educational Publications. Rojahn, J. (1984). Self-injurious behaviour in institutionalised, severely/profoundly retarded adults: Prevalence data and staff agreement. Journal of Behavioral Assessment, 6, 13–27. Rojahn, J. (1986). Self-injurious behaviour and stereotypic behaviour of non-institutionalised mentally retarded people: Prevalence and classification. American Journal of Mental Deficiency, 91, 268–276. Rojahn, J., Aman, M. G., Matson, J. L., & Mayville, E. (2003). The aberrant behavior checklist and the behavior problems inventory: Convergent and divergent validity. Research in Developmental Disabilities, 24, 391–404. Rojahn, J., & Helsel, W. J. (1991). The aberrant behavior checklist with children and adolescents with dual diagnosis. Journal of Autism and Developmental Disorders, 21, 17–28. Rojahn, J., Matson, J. L., Lott, D., Esbensen, A. J., & Smalls, Y. (2001). The behavior problems inventory: An instrument for the assessment of self-injury, stereotyped behavior and aggression/destruction in individuals with developmental disabilities. Journal of Autism and Developmental Disorders, 31, 577–588. Rojahn, J., Matlock, S. T., & Tasse´, M. J. (2000). The stereotyped behavior scale: Psychometric properties and norms. Research in Developmental Disabilities, 21, 437–454. Rojahn, J., Polster, L. M., & Mulick, J. A. (1989). Reliability of the behavior problems inventory. Journal of the Multihandicapped Person, 2, 283–293.
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