- Email: [email protected]
Confirmatory factor analysis of the Quitting Time for Alcohol Questionnaire
Addictive Behaviors 28 (2003) 1487 – 1495
Short Communication
Confirmatory factor analysis of the Quitting Time for Alcohol Questionnaire Tian P.S. Oei*, Penelope Hasking School of Psychology, University of Queensland, Brisbane, QLD 4072, Australia
Abstract The Quitting Time for Alcohol Questionnaire (QTAQ) was developed by Oei et al. in 1999 to provide a tool that could assess the reasons why a person would cease drinking in a single episode. While this tool was observed to have good psychometric properties, including reliability and validity, the findings have not been replicated, in particular, confirmatory factor analysis has not been provided. This study, using 300 community drinkers, attempted to address this shortcoming. Confirmatory factor analysis supported Oei et al.’s [Addict. Behav. 24 (1999) 383.] research, indicating that the community sample had a three-factor underlying structure, leading to one total score. The findings show that the QTAQ is a valid and reliable instrument for assessing reasons why people cease drinking in a single session. D 2002 Elsevier Science Ltd. All rights reserved. Keywords: Drinking behaviour; Factor analysis; Alcohol; Psychopathology
1. Introduction Over the past few decades, there has been resurgence in the investigation of alcohol consumption. This has mainly focussed on the reasons why people start drinking (e.g. Carpenter & Hasin, 1998; Williams & Clark, 1998) and how to minimise problem drinking behaviour (e.g. Drake, Mueser, Clark, & Wallach, 1996; Oei & Loveday, 1997). Consequently many theories have arisen in an attempt to explain drinking behaviour.
* Corresponding author. Tel.: +61-7-3365-6230; fax: +61-7-3365-4466. E-mail address: [email protected] (T.P.S. Oei). 0306-4603/$ – see front matter D 2002 Elsevier Science Ltd. All rights reserved. doi:10.1016/S0306-4603(02)00268-X
1488
T.P.S. Oei, P. Hasking / Addictive Behaviors 28 (2003) 1487–1495
While this line of work has made significant contributions to the understanding of alcohol problems, a full understanding of problem drinking is far from complete. One reason for this is that alcohol problems are defined by an inability to cease drinking, rather than from factors contributing to having a drink. Many people who start drinking remain social drinkers. Consequently, the investigation of why people stop drinking is just as important as research establishing the reasons why people might start drinking. However, there has been comparatively little research into why people stop drinking. Further, it is not only important to understand what motivates a person with a drinking problem to permanently control or cease their drinking but also to understand the motivation behind cessation of drinking in a single drinking session. What is it that makes a person decide which drink is to be the last of the evening? (See Oei, Sweeten, Dingle, & Chalmers, 1999.) This is an important question as the answer could not only provide insight into the difference between a social drinker and an alcohol-dependent drinker but could also aid in the treatment of alcohol dependence. Understanding the reasons why a person ceases to drink at the end of a particular session may give some understanding of the factors important in controlled drinking, which could be capitalised on in the rehabilitation of problem drinkers. Oei et al. (1999) recently devised a questionnaire designed to address this issue. The Quitting Time for Alcohol Questionnaire (QTAQ) comprised 23 items relating to a person’s reasons to cease drinking in a single drinking session. The development of this questionnaire provides an efficient way of predicting reasons for alcohol cessation, in an area where experiments either in laboratory or naturalistic settings (e.g. a bar) are time consuming and expensive. After initial testing on a community sample obtained from businesses and sporting facilities and a university student sample, the researchers revealed three factors, which significantly predicted a person’s reasons to stop drinking. These three factors can best be described as internal status (QTAQ-IS), avoidance/adherence (QTAQ-AA), and immediate context (QTAQ-IC). Internal status reflects reasons related to emotional and perceptual states within an individual. Avoidance/adherence reflects both avoidance of negative consequences arising from continued drinking and adherence to drinking boundaries. The last factor, immediate context, reflects reasons related to aspects of the drinkers immediate environment. All three factors significantly predicted alcohol cessation in both the community and student samples and reported high internal consistency and test–retest reliability (Oei et al., 1999). However, despite good psychometric properties in the initial development of the questionnaire, the QTAQ has never been subjected to confirmatory factor analysis. As confirmatory factor analysis is a more stringent technique than exploratory factor analysis, designed to test the underlying theoretical structure about latent processes (Tabachnick & Fidell, 1996), this is an essential step in the validation of the QTAQ. Hence, it is the aim of this study to extend Oei et al.’s (1999) study and enhance the validation of the QTAQ by providing confirmatory factor analysis in a community sample. A confirmatory factor analysis should reveal the same three factors proposed by Oei et al.
T.P.S. Oei, P. Hasking / Addictive Behaviors 28 (2003) 1487–1495
1489
(1999), however, in constructing a new questionnaire, it is essential to confirm that the same items load on these factors.
2. Method 2.1. Participants The sample consisted of 300 participants who responded to media advertising in the Brisbane metropolitan area. A total of 143 males and 157 females with a mean age of 32.18 (S.D. = 11.75) agreed to participate. Most of the sample were born in Australia (76%), with the remainder of the sample originating in Europe, New Zealand, Asia, USA, Canada, Solomon Islands, Ireland, New Guinea, Africa, and Portugal. 2.2. Measures 2.2.1. The QTAQ (Oei et al., 1999) This 23-item questionnaire is described in detail by Oei et al. (1999), hence, only a summary is provided here. Each statement on the questionnaire reflects a possible reason for someone to stop drinking in a single drinking episode, with each item answered on a Likerttype scale ranging from 1 = does not apply to me to 5 = always applies to me. High internal consistency (Cronbach’s alpha=.71) and test–retest reliability (r=.76) were reported by the researchers. The questionnaire can be seen in Appendix A. 2.2.2. Demographic survey Participants also completed a short demographic data sheet. Information such as gender, age, and country of birth were recorded. 2.3. Procedure A questionnaire was mailed to all participants who responded to the advertisements. A stamped, self-addressed envelope was included to allow participants to mail their completed questionnaires to the researchers. Each questionnaire included an information sheet about the experiment and participants were ensured that confidentiality was to be maintained.
3. Results 3.1. Statistical assumptions Preliminary analysis of the data revealed that all assumptions of confirmatory factor analysis were met. There was no evidence of multicollinearity and outliers were detected
1490
T.P.S. Oei, P. Hasking / Addictive Behaviors 28 (2003) 1487–1495
Fig. 1. Hypothesized structural model for QTAQ.
and deleted using Mahalanobis distance [c2(23) = 49.73]. This resulted in two cases being deleted from the analysis. 3.2. Confirmatory factor analysis EQS was used to perform a confirmatory factor analysis for the community sample. The hypothesised model is depicted in Fig. 1. Based on previous work (Oei et al., 1999), the sample is proposed to fit a three-factor solution. The 23 items of the QTAQ are proposed to comprise the subscale factors (QTAQ-IC, QTAQ-AA, and QTAQ-IS), with all factors leading to a sum total score. In order to test the factor structure, two confirmatory factor analyses were performed. The first model tested the loading of items onto the three proposed
Table 1 Fit indices and residual statistics for confirmatory factor analyses Model
Three factorsa Three factors and totalb a b
AIC
CAIC
Null model
Observed model
Null model
5887.41 5871.88
640.59 7.77
4699.04 4684.37
CFI
NFI
NNFI
RMR
SRMR
RMSEA
0.87 0.98
0.84 0.95
0.82 0.96
0.68 0.08
0.38 0.04
0.12 0.06
Observed model 233.07 735.30
The model represents 23 items loading onto three factors of QTAQ-IC, QTAQ-AA, and QTAQ-IS. The model represents 23 items loading onto three factors, which then load onto a cumulative total score.
T.P.S. Oei, P. Hasking / Addictive Behaviors 28 (2003) 1487–1495
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Fig. 2. Results of the confirmatory factor analysis on the QTAQ for the full model. Items are presented in factor order. Item numbers in brackets represent corresponding items on the questionnaire.
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T.P.S. Oei, P. Hasking / Addictive Behaviors 28 (2003) 1487–1495
Table 2 Correlations between factors for community sample QTAQ-IC QTAQ-AA QTAQ-IS
QTAQ-AA
QTAQ-IS
QTAQ
.21**
.41** .32**
.57** .85** .72**
** P < .01.
factors. Secondly, the full model was examined, with items loading onto the three subscales, which, in turn, load onto a total score. Maximum likelihood estimation was used to estimate these models. The first model examining items loading onto the three proposed factors was found to be a moderate fit to the data. While the null model was easily rejected [c2(253) = 6393.41, P < .001], the observed model [c2(186) = 1012.59, P < .001] was observed to have relatively low fit indices and high residual statistics (see Table 1). The second model, with test items, factors, and a total score, was observed to be an acceptable fit to the data. The null model, assuming no relationship between variables was rejected [c2(253) = 6377.88, P < .001], while support was found for the hypothesised model [c2(155) = 302.23, P < .001]. A range of fit indices supported the three-factor and total score solution and model fit for this data (see Table 1). The Akaike Information Criterion (AIC) dropped significantly between the independence model and the observed model, as did the Consistent Akaike Information Criterion (CAIC). The decrease in these indices supports the fit of this model. The comparative fit index (CFI) was high, again indicating an adequate fit to the data. The Beniler–Bonnett normed (NFI) and nonnormed fit indices (NNFI) revealed a similar pattern (see Table 1). The average of the standardised residuals was low (0.02), with no residuals above 0.3, the arbitrary cutoff (Tabachnick & Fidell, 1996). The stem leaf plot indicated that the residuals were centred around zero and is symmetrically distributed. Fig. 2 shows the observed model, including standardised test statistics. All residual estimates were low (see Table 1), indicating that no further information is able to obtained by this model. Correlations between these factors are given in Table 2. All factors were found to significantly correlate with each other, and with the total score. Means for QTAQ-IC (17.97, S.D. = 1.93) and for QTAQ-IS (9.38, S.D. = 3.48) were found to be substantially lower in this sample than in the original study. The third factor, QTAQ-AA was found to have a mean (18.99, S.D. = 8.23) comparable to that in the original study (cf. Oei et al., 1999).
4. Discussion It was the aim of this study to extend the work of Oei et al. (1999) in creating a questionnaire to assess the reasons why people stop drinking in a single drinking session.
T.P.S. Oei, P. Hasking / Addictive Behaviors 28 (2003) 1487–1495
1493
Confirmatory factor analysis revealed that the three-factor solution, with each factor summing to a total score, was an accurate model to represent this data. The 23-item QTAQ with three factors proposed by Oei et al. (1999) is an adequate tool for assessing reason’s people in the community stop drinking in a single drinking session. The three factors: internal status, avoidance/adherence, and immediate context, were found to underlie the construct and all items loaded on the same factors as in the original investigation. These three factors were then shown to load on a single total score. The utility of the QTAQ, both as a research and clinical tool, is widespread. Identification of reasons why people stop drinking at the end of a drinking session has immense potential both for prevention and rehabilitation of problem drinking (see Oei et al., 1999). In identifying these reasons, treatment programs can capitalise not only on research identifying factors relating to maintenance of drinking, but also factors important in stopping drinking. This two-pronged attack is likely to be more effective in both prevention and treatment than either focus alone. The QTAQ is quick and easy to administer and score, making it an ideal instrument to use in research, brief interventions, and counselling. Immediate identification of reasons why an individual may cease drinking in a single drinking session can be quickly capitalised on for immediate treatment benefits. Naturally, the QTAQ will require validation in an alcohol-dependent sample should the questionnaire be used in such a sample. This laboratory is currently determining the utility of the QTAQ in an alcohol-dependent sample. Reasons why a person ceases drinking also tie in with a motivation model of alcohol use proposed by Cox and Klinger (1988). These researchers propose that the decision to drink or not to drink is determined by emotional factors, the situation a person is in, and positive and negative incentives derived from continued drinking—the same factors assessed by the QTAQ. In outlining treatment implications of their model, the researchers acknowledge that motivation to stop drinking should address these factors. The QTAQ provides a short, valid, and reliable means of assessing these factors in relation to drinking cessation, making it an ideal tool for use in motivational interviewing and motivationfocussed research projects. One result requires explanation. The reason for lower mean scores on the QTAQ-IS and QTAQ-IC scales in this sample compared to the Oei et al. (1999) original study is unclear. In searching for an explanation, gender differences and differences in alcohol consumption between the samples were investigated, however, no differences were apparent. Consequently, it appears that for some unknown reasons, participants in this sample tended to opt for lower scores on the questionnaire. However, despite any differences in the nature of the samples, the psychometric properties of the QTAQ are sound. That is, regardless of the nature of the sample, the relationship between the items and factors of the QTAQ could be confirmed in this sample. This study and the earlier publication (Oei et al., 1999) has provided validation of the QTAQ as a tool for assessing reasons why community drinkers cease drinking in a single drinking session. It is concluded that the QTAQ provides a short, valid, and reliable method of assessing these reasons that has both research and clinical utility.
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T.P.S. Oei, P. Hasking / Addictive Behaviors 28 (2003) 1487–1495
Appendix A. The Quitting Time for Alcohol Questionnaire Directions: Listed below are 23 statements describing reasons a person might stop drinking alcohol after she/he has had one or more drinks. Please read each statement carefully and indicate during the past 4 weeks how much each statement has applied to you by placing a circle at the most appropriate number for each statement. 1 = does not apply to me; 2 = sometimes applies to me; 3 = applies 50% of the time; 4 = usually applies to me; 5 = always applies to me. 1. 2. 3. 4. 5. 6. 7.
I am getting angry I am afraid I will be stopped by the police I do not like the place I am drinking in I am getting aggressive I am going to do other activities There is no more alcohol available I am worried about what I will say if I drink more 8. I do not want to damage my physical health 9. I do not like who I am drinking with 10. I am afraid I will not be able to stop if I drink more 11. I do not want to be sick the next day or later the same day 12. I was ‘‘stood-up’’: My expected drinking partners/friends did not arrive 13. My behaviour is becoming socially inappropriate 14. I have reached the drinking limit I set for myself 15. I plan on using other mind-altering drugs after I drink alcohol 16. I am getting depressed 17. I have to take my drinking partner/friend home 18. I have taken other mind-altering drugs before I started drinking 19. I am getting sad 20. I do not want to damage my brain 21. The drinking place closes 22. I have to go to work the next day 23. I ran out of money
1 1 1 1 1 1 1
2 2 2 2 2 2 2
3 3 3 3 3 3 3
4 4 4 4 4 4 4
5 5 5 5 5 5 5
1 1 1
2 2 2
3 3 3
4 4 4
5 5 5
1
2
3
4
5
1
2
3
4
5
1 1
2 2
3 3
4 4
5 5
1
2
3
4
5
1 1 1
2 2 2
3 3 3
4 4 4
5 5 5
1 1 1 1 1
2 2 2 2 2
3 3 3 3 3
4 4 4 4 4
5 5 5 5 5
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References Carpenter, K. M., & Hasin, D. (1998). A prospective evaluation of the relation between reasons for drinking and DSM alcohol-use disorders. Addictive Behaviors, 23(1), 41 – 46. Cox, W. M., & Klinger, E. (1988). A motivational model for alcohol use. Journal of Abnormal Psychology, 97, 168 – 180. Drake, R. E., Mueser, K. T., Clark, R. E., & Wallach, M. A. (1996). The course, treatment, and outcome of substance disorder in persons with severe mental illness. American Journal of Orthopsychiatry, 66(1), 42 – 49. Oei, T. P. S., & Loveday, W. A. L. (1997). Management of co-morbid anxiety and alcohol disorders: Parallel treatment of disorders. Drug and Alcohol Review, 16, 261 – 274. Oei, T. P. S., Sweeton, J., Dingle, G., & Chalmers, K. (1999). Psychometric properties of a Quitting Time for Alcohol Questionnaire: Factor structure, reliability and validity. Addictive Behaviors, 24(3), 383 – 398. Tabachnick, B., & Fidell, L. (1996). Using multivariate statistics (3rd ed.). California: Harper Collins. Williams, A., & Clark, D. (1998). Alcohol consumption in university students: The role of reasons for drinking, coping strategies, expectancies, and personality traits. Addictive Behaviors, 23(3), 371 – 378.
Short Communication
Confirmatory factor analysis of the Quitting Time for Alcohol Questionnaire Tian P.S. Oei*, Penelope Hasking School of Psychology, University of Queensland, Brisbane, QLD 4072, Australia
Abstract The Quitting Time for Alcohol Questionnaire (QTAQ) was developed by Oei et al. in 1999 to provide a tool that could assess the reasons why a person would cease drinking in a single episode. While this tool was observed to have good psychometric properties, including reliability and validity, the findings have not been replicated, in particular, confirmatory factor analysis has not been provided. This study, using 300 community drinkers, attempted to address this shortcoming. Confirmatory factor analysis supported Oei et al.’s [Addict. Behav. 24 (1999) 383.] research, indicating that the community sample had a three-factor underlying structure, leading to one total score. The findings show that the QTAQ is a valid and reliable instrument for assessing reasons why people cease drinking in a single session. D 2002 Elsevier Science Ltd. All rights reserved. Keywords: Drinking behaviour; Factor analysis; Alcohol; Psychopathology
1. Introduction Over the past few decades, there has been resurgence in the investigation of alcohol consumption. This has mainly focussed on the reasons why people start drinking (e.g. Carpenter & Hasin, 1998; Williams & Clark, 1998) and how to minimise problem drinking behaviour (e.g. Drake, Mueser, Clark, & Wallach, 1996; Oei & Loveday, 1997). Consequently many theories have arisen in an attempt to explain drinking behaviour.
* Corresponding author. Tel.: +61-7-3365-6230; fax: +61-7-3365-4466. E-mail address: [email protected] (T.P.S. Oei). 0306-4603/$ – see front matter D 2002 Elsevier Science Ltd. All rights reserved. doi:10.1016/S0306-4603(02)00268-X
1488
T.P.S. Oei, P. Hasking / Addictive Behaviors 28 (2003) 1487–1495
While this line of work has made significant contributions to the understanding of alcohol problems, a full understanding of problem drinking is far from complete. One reason for this is that alcohol problems are defined by an inability to cease drinking, rather than from factors contributing to having a drink. Many people who start drinking remain social drinkers. Consequently, the investigation of why people stop drinking is just as important as research establishing the reasons why people might start drinking. However, there has been comparatively little research into why people stop drinking. Further, it is not only important to understand what motivates a person with a drinking problem to permanently control or cease their drinking but also to understand the motivation behind cessation of drinking in a single drinking session. What is it that makes a person decide which drink is to be the last of the evening? (See Oei, Sweeten, Dingle, & Chalmers, 1999.) This is an important question as the answer could not only provide insight into the difference between a social drinker and an alcohol-dependent drinker but could also aid in the treatment of alcohol dependence. Understanding the reasons why a person ceases to drink at the end of a particular session may give some understanding of the factors important in controlled drinking, which could be capitalised on in the rehabilitation of problem drinkers. Oei et al. (1999) recently devised a questionnaire designed to address this issue. The Quitting Time for Alcohol Questionnaire (QTAQ) comprised 23 items relating to a person’s reasons to cease drinking in a single drinking session. The development of this questionnaire provides an efficient way of predicting reasons for alcohol cessation, in an area where experiments either in laboratory or naturalistic settings (e.g. a bar) are time consuming and expensive. After initial testing on a community sample obtained from businesses and sporting facilities and a university student sample, the researchers revealed three factors, which significantly predicted a person’s reasons to stop drinking. These three factors can best be described as internal status (QTAQ-IS), avoidance/adherence (QTAQ-AA), and immediate context (QTAQ-IC). Internal status reflects reasons related to emotional and perceptual states within an individual. Avoidance/adherence reflects both avoidance of negative consequences arising from continued drinking and adherence to drinking boundaries. The last factor, immediate context, reflects reasons related to aspects of the drinkers immediate environment. All three factors significantly predicted alcohol cessation in both the community and student samples and reported high internal consistency and test–retest reliability (Oei et al., 1999). However, despite good psychometric properties in the initial development of the questionnaire, the QTAQ has never been subjected to confirmatory factor analysis. As confirmatory factor analysis is a more stringent technique than exploratory factor analysis, designed to test the underlying theoretical structure about latent processes (Tabachnick & Fidell, 1996), this is an essential step in the validation of the QTAQ. Hence, it is the aim of this study to extend Oei et al.’s (1999) study and enhance the validation of the QTAQ by providing confirmatory factor analysis in a community sample. A confirmatory factor analysis should reveal the same three factors proposed by Oei et al.
T.P.S. Oei, P. Hasking / Addictive Behaviors 28 (2003) 1487–1495
1489
(1999), however, in constructing a new questionnaire, it is essential to confirm that the same items load on these factors.
2. Method 2.1. Participants The sample consisted of 300 participants who responded to media advertising in the Brisbane metropolitan area. A total of 143 males and 157 females with a mean age of 32.18 (S.D. = 11.75) agreed to participate. Most of the sample were born in Australia (76%), with the remainder of the sample originating in Europe, New Zealand, Asia, USA, Canada, Solomon Islands, Ireland, New Guinea, Africa, and Portugal. 2.2. Measures 2.2.1. The QTAQ (Oei et al., 1999) This 23-item questionnaire is described in detail by Oei et al. (1999), hence, only a summary is provided here. Each statement on the questionnaire reflects a possible reason for someone to stop drinking in a single drinking episode, with each item answered on a Likerttype scale ranging from 1 = does not apply to me to 5 = always applies to me. High internal consistency (Cronbach’s alpha=.71) and test–retest reliability (r=.76) were reported by the researchers. The questionnaire can be seen in Appendix A. 2.2.2. Demographic survey Participants also completed a short demographic data sheet. Information such as gender, age, and country of birth were recorded. 2.3. Procedure A questionnaire was mailed to all participants who responded to the advertisements. A stamped, self-addressed envelope was included to allow participants to mail their completed questionnaires to the researchers. Each questionnaire included an information sheet about the experiment and participants were ensured that confidentiality was to be maintained.
3. Results 3.1. Statistical assumptions Preliminary analysis of the data revealed that all assumptions of confirmatory factor analysis were met. There was no evidence of multicollinearity and outliers were detected
1490
T.P.S. Oei, P. Hasking / Addictive Behaviors 28 (2003) 1487–1495
Fig. 1. Hypothesized structural model for QTAQ.
and deleted using Mahalanobis distance [c2(23) = 49.73]. This resulted in two cases being deleted from the analysis. 3.2. Confirmatory factor analysis EQS was used to perform a confirmatory factor analysis for the community sample. The hypothesised model is depicted in Fig. 1. Based on previous work (Oei et al., 1999), the sample is proposed to fit a three-factor solution. The 23 items of the QTAQ are proposed to comprise the subscale factors (QTAQ-IC, QTAQ-AA, and QTAQ-IS), with all factors leading to a sum total score. In order to test the factor structure, two confirmatory factor analyses were performed. The first model tested the loading of items onto the three proposed
Table 1 Fit indices and residual statistics for confirmatory factor analyses Model
Three factorsa Three factors and totalb a b
AIC
CAIC
Null model
Observed model
Null model
5887.41 5871.88
640.59 7.77
4699.04 4684.37
CFI
NFI
NNFI
RMR
SRMR
RMSEA
0.87 0.98
0.84 0.95
0.82 0.96
0.68 0.08
0.38 0.04
0.12 0.06
Observed model 233.07 735.30
The model represents 23 items loading onto three factors of QTAQ-IC, QTAQ-AA, and QTAQ-IS. The model represents 23 items loading onto three factors, which then load onto a cumulative total score.
T.P.S. Oei, P. Hasking / Addictive Behaviors 28 (2003) 1487–1495
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Fig. 2. Results of the confirmatory factor analysis on the QTAQ for the full model. Items are presented in factor order. Item numbers in brackets represent corresponding items on the questionnaire.
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Table 2 Correlations between factors for community sample QTAQ-IC QTAQ-AA QTAQ-IS
QTAQ-AA
QTAQ-IS
QTAQ
.21**
.41** .32**
.57** .85** .72**
** P < .01.
factors. Secondly, the full model was examined, with items loading onto the three subscales, which, in turn, load onto a total score. Maximum likelihood estimation was used to estimate these models. The first model examining items loading onto the three proposed factors was found to be a moderate fit to the data. While the null model was easily rejected [c2(253) = 6393.41, P < .001], the observed model [c2(186) = 1012.59, P < .001] was observed to have relatively low fit indices and high residual statistics (see Table 1). The second model, with test items, factors, and a total score, was observed to be an acceptable fit to the data. The null model, assuming no relationship between variables was rejected [c2(253) = 6377.88, P < .001], while support was found for the hypothesised model [c2(155) = 302.23, P < .001]. A range of fit indices supported the three-factor and total score solution and model fit for this data (see Table 1). The Akaike Information Criterion (AIC) dropped significantly between the independence model and the observed model, as did the Consistent Akaike Information Criterion (CAIC). The decrease in these indices supports the fit of this model. The comparative fit index (CFI) was high, again indicating an adequate fit to the data. The Beniler–Bonnett normed (NFI) and nonnormed fit indices (NNFI) revealed a similar pattern (see Table 1). The average of the standardised residuals was low (0.02), with no residuals above 0.3, the arbitrary cutoff (Tabachnick & Fidell, 1996). The stem leaf plot indicated that the residuals were centred around zero and is symmetrically distributed. Fig. 2 shows the observed model, including standardised test statistics. All residual estimates were low (see Table 1), indicating that no further information is able to obtained by this model. Correlations between these factors are given in Table 2. All factors were found to significantly correlate with each other, and with the total score. Means for QTAQ-IC (17.97, S.D. = 1.93) and for QTAQ-IS (9.38, S.D. = 3.48) were found to be substantially lower in this sample than in the original study. The third factor, QTAQ-AA was found to have a mean (18.99, S.D. = 8.23) comparable to that in the original study (cf. Oei et al., 1999).
4. Discussion It was the aim of this study to extend the work of Oei et al. (1999) in creating a questionnaire to assess the reasons why people stop drinking in a single drinking session.
T.P.S. Oei, P. Hasking / Addictive Behaviors 28 (2003) 1487–1495
1493
Confirmatory factor analysis revealed that the three-factor solution, with each factor summing to a total score, was an accurate model to represent this data. The 23-item QTAQ with three factors proposed by Oei et al. (1999) is an adequate tool for assessing reason’s people in the community stop drinking in a single drinking session. The three factors: internal status, avoidance/adherence, and immediate context, were found to underlie the construct and all items loaded on the same factors as in the original investigation. These three factors were then shown to load on a single total score. The utility of the QTAQ, both as a research and clinical tool, is widespread. Identification of reasons why people stop drinking at the end of a drinking session has immense potential both for prevention and rehabilitation of problem drinking (see Oei et al., 1999). In identifying these reasons, treatment programs can capitalise not only on research identifying factors relating to maintenance of drinking, but also factors important in stopping drinking. This two-pronged attack is likely to be more effective in both prevention and treatment than either focus alone. The QTAQ is quick and easy to administer and score, making it an ideal instrument to use in research, brief interventions, and counselling. Immediate identification of reasons why an individual may cease drinking in a single drinking session can be quickly capitalised on for immediate treatment benefits. Naturally, the QTAQ will require validation in an alcohol-dependent sample should the questionnaire be used in such a sample. This laboratory is currently determining the utility of the QTAQ in an alcohol-dependent sample. Reasons why a person ceases drinking also tie in with a motivation model of alcohol use proposed by Cox and Klinger (1988). These researchers propose that the decision to drink or not to drink is determined by emotional factors, the situation a person is in, and positive and negative incentives derived from continued drinking—the same factors assessed by the QTAQ. In outlining treatment implications of their model, the researchers acknowledge that motivation to stop drinking should address these factors. The QTAQ provides a short, valid, and reliable means of assessing these factors in relation to drinking cessation, making it an ideal tool for use in motivational interviewing and motivationfocussed research projects. One result requires explanation. The reason for lower mean scores on the QTAQ-IS and QTAQ-IC scales in this sample compared to the Oei et al. (1999) original study is unclear. In searching for an explanation, gender differences and differences in alcohol consumption between the samples were investigated, however, no differences were apparent. Consequently, it appears that for some unknown reasons, participants in this sample tended to opt for lower scores on the questionnaire. However, despite any differences in the nature of the samples, the psychometric properties of the QTAQ are sound. That is, regardless of the nature of the sample, the relationship between the items and factors of the QTAQ could be confirmed in this sample. This study and the earlier publication (Oei et al., 1999) has provided validation of the QTAQ as a tool for assessing reasons why community drinkers cease drinking in a single drinking session. It is concluded that the QTAQ provides a short, valid, and reliable method of assessing these reasons that has both research and clinical utility.
1494
T.P.S. Oei, P. Hasking / Addictive Behaviors 28 (2003) 1487–1495
Appendix A. The Quitting Time for Alcohol Questionnaire Directions: Listed below are 23 statements describing reasons a person might stop drinking alcohol after she/he has had one or more drinks. Please read each statement carefully and indicate during the past 4 weeks how much each statement has applied to you by placing a circle at the most appropriate number for each statement. 1 = does not apply to me; 2 = sometimes applies to me; 3 = applies 50% of the time; 4 = usually applies to me; 5 = always applies to me. 1. 2. 3. 4. 5. 6. 7.
I am getting angry I am afraid I will be stopped by the police I do not like the place I am drinking in I am getting aggressive I am going to do other activities There is no more alcohol available I am worried about what I will say if I drink more 8. I do not want to damage my physical health 9. I do not like who I am drinking with 10. I am afraid I will not be able to stop if I drink more 11. I do not want to be sick the next day or later the same day 12. I was ‘‘stood-up’’: My expected drinking partners/friends did not arrive 13. My behaviour is becoming socially inappropriate 14. I have reached the drinking limit I set for myself 15. I plan on using other mind-altering drugs after I drink alcohol 16. I am getting depressed 17. I have to take my drinking partner/friend home 18. I have taken other mind-altering drugs before I started drinking 19. I am getting sad 20. I do not want to damage my brain 21. The drinking place closes 22. I have to go to work the next day 23. I ran out of money
1 1 1 1 1 1 1
2 2 2 2 2 2 2
3 3 3 3 3 3 3
4 4 4 4 4 4 4
5 5 5 5 5 5 5
1 1 1
2 2 2
3 3 3
4 4 4
5 5 5
1
2
3
4
5
1
2
3
4
5
1 1
2 2
3 3
4 4
5 5
1
2
3
4
5
1 1 1
2 2 2
3 3 3
4 4 4
5 5 5
1 1 1 1 1
2 2 2 2 2
3 3 3 3 3
4 4 4 4 4
5 5 5 5 5
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