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Use of the life optimism test among adolescents in a clinical setting: A report of reliability testing
JOURNAL OF ADOLESCENT HEALTH 1997;21:218-220
ADOLESCENT HEALTH BRIEF
Use of the Life Optimism Test Among Adolescents in a Clinical Setting: A Report of Reliability Testing ELIZABETH G O O D M A N , M.D., J O H N R. KNIGHT, M.D., A N D ROBERT H. D u R A N T , Ph.D.
This study examined the consistency and reliability o f the Life Optimism Test (LOT) among patients attending an adolescent medicine clinic. The LOT had good internal consistency (Cronbach's alpha ranging from 0.56 at pretest to 0.76 at posttest) and good 1-week test-retest reliability (intraclass correlation = 0.84). These data support u s e o f the LOT to measure optimism among adolescents. © Society f o r Adolescent Medicine, 1997 KEY WORDS,"
Optimism Adolescents Reliability Although optimism is generally viewed as a positive attribute, this trait has received little systematic evaluation among adolescents. Optimism is defined as the tendency to believe one will experience positive outcomes in life (1). In studies of adults, optimism has been associated with beneficial health effects (2,3). Among college students, higher optimism has been associated with better adjustment to college (4) and higher expected levels of academic achievement (5). However, higher optimism was positively correlated with sexual risk behaviors among human immunodeficiency virus (HIV)-negative homosexual men (6) and less use of HIV testing services among female adolescents engaging in risk behaviors (7). The Life Optimism Test (LOT), the instrument used to measure optimism in these studies, has not From the Division of Adolescent/Young Adult Medicine (E.G., R.H.D.) and the Division of General Pediatrics (J.R.K.), Children's Hospital, Boston, Massachusetts. Address reprint requests to: Elizabeth Goodman, M.D., Children's Hospital, 300 Longwood Avenue, Boston, MA 02115. Manuscript accepted April 12, 1997. 1054-139X/97/$17.00 PII $1054-139X(97)00123-7
been validated among teens. The Generalized Expectancy for Success Scale, another measure of optimism, has been used in a study of Japanese adolescents (10). This measure was developed to measure adults' expectations of obtaining future goals and does not assess optimism as a trait as does the LOT. The LOT is an eight item Likert-type scale, with four filler items (Table 1). The psychometric properties of the LOT were tested on a predominantly white undergraduate college population and were reported to include good convergent and discriminant validity, Cronbach's alpha of 0.76, and 4-week testretest reliability of 0.79 (1). This study examined the internal consistency and one-week test-retest reliability of the LOT in an ethnically diverse sample of adolescent patients to determine its applicability in research with adolescents in an urban medical clinic setting.
Methods Sample Description and Overview This analysis is based on data collected as part of a study of the psychometric properties of two scales: the Problem-Oriented Screening Instrument for Teenagers (POSIT) and the LOT. Analyses of the POSIT scale have been published elsewhere (8). The study took place at an urban, hospital-based adolescent medicine clinic which served both inner-city and suburban youth. Fifteen- to 18-year-old patients who were being seen for well and scheduled sick adolescent visits or for walk-in appointments for non-urgent reasons were eligible to participate. Patients were excluded if they were being seen for acute problems or if their medical provider believed that completing the questionnaire would be too
© Society for Adolescent Medicine, 1997 Published by Elsevier Science Inc., 655 Avenue of the Americas, New York, NY 10010
October 1997
Table 1. Life Optimism Test Scale Items 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11.
In uncertain times, I usually expect the best. It's easy for m e to relax (filler item). If something can go w r o n g for me, it will. I always look on the bright side of things. I'm always optimistic about m y future. I enjoy m y friends a lot (filler item). It's important for m e to keep busy (filler item). I hardly ever expect things to go m y way. Things never work out the way I w a n t them to. I don't get upset too easily (filler item). I'm a believer in the idea that "every cloud has a silver lining." 12. I rarely count on good things h a p p e n i n g to me.
stressful. Based on these criteria, three patients newly diagnosed as pregnant, three patients being seen for anorexia nervosa, and one patient being evaluated for possible sexual assault were excluded. One hundred seventy-three patients agreed to participate. Information on the number of subjects who refused to participate was not kept. Subjects were enrolled by a trained research assistant not involved in the medical care process, who explained the purpose of the study and that the questionnaire would be anonymous. The research assistant obtained informed consent from the patient, who then completed the questionnaire ("pretest LOT"). Ninety percent (156 of 173) provided adequate data for LOT scale construction and comprise the study sample. After completing the questionnaire, subjects made an appointment to return for one week to complete the follow-up questionnaire. Eighty-six subjects (55%) returned for their follow-up appointment, 85 of w h o m provided adequate data for scale construction ("postest LOT"). There was no difference in age, gender, or race between those who completed the postest and those who did not. Subjects received a small gift certificate from a local merchant (i.e., for a slice of pizza) for completing the follow-up questionnaire. The study received approval from the hospital's human subjects committee. The 156 subjects reflected the population served by the clinic, with 71% being female, 17% white, 17% of Hispanic ethnicity, 42% African-American, and 1% Asian. The mean grade was 10.9 + 1.0 (range 10-13). The mean age was 16.3 + 1.1 years.
Statistical Analysis A repeated-measures analysis of variance (ANOVA) was computed on the pretest and posttest LOTs. One-week test-retest reliability was then computed
LIFE OPTIMISM TEST A M O N G ADOLESCENTS
219
from the ANOVA results using Winer's unbiased estimate of the intraclass correlation (9). Internal consistency was computed using Cronbach's alpha. Statistical computations except the intraclass correlation were performed using SPSS for Windows. Means are reported with standard deviations.
Results The mean LOT was 18.8 + 5.3 among: females and 20.9 + 5.4 among males. Because this difference was not statistically significant, males and females were combined for the remaining analyses. The mean LOT score was 19.1 + 4.7 at pretest and 119.3 + 5.4 at posttest. Among those who returned for follow-up, the mean pretest LOT score was 19.2 + .5.2. The mean pretest LOT among those who failed to return for follow-up was 18.9 + 4.1. This difference was not significant. The LOT demonstrated adequate internal consistency. Pretest LOT Cronbach's alpha was 0.56. Item analysis indicated that when one item (Item 1) was deleted ("In uncertain times, I usually expect the best"), the Cronbach's alpha increased to 0.58. Subgroup analyses between those who did and did not return for follow-up revealed that the pattern of answering Item I differed between these groups and contributed significantly to the Cronbach's alpha. Among those who returned for follow-up, Cronbach's alpha on the pretest LOT was 0.64. When Item 1 was deleted, the Cronbach's alpha decreased to 0.60. Among those who did not return :for follow-up, pretest Cronbach's alpha was 0.44. This increased to 0.55 when Item 1 was deleted. On posttest, Cronbach's alpha was 0.76. Item analysis of the posttest LOT indicated that deletion of any item would decrease the consistency. Deletion of Item 1 made a negligible decrease in the Cronbach's alpha (0.0008). The LOT had a good test-retest intraclass correlation of 0.84.
Discussion This study demonstrates that the LOT will reliably measure optimism among mid-adolescents in an adolescent medicine clinic. There was good testretest reliability and internal consistency. The increase in Cronbach's alpha noted between administrations of the instrument suggests that that internal consistency reflects not only properties of the instrument, but also the individual's familiarity with the measure. The changes in internal consistency related to deletion of Item 1 suggest that those who did not
220
GOODMAN ET AL.
complete follow-up were less consistent in how they responded to this item, compared to Items 2-8. Longitudinal studies using this instrument should consider computing the LOT only for those who complete follow-up. The Cronbach's alphas reported here are consistent with that reported by Goodman et al. (0.61) in their sample of 124 predominantly African-American females attending a health maintenance organization (7). The means for females from this sample are also slightly lower than those reported by Scheier and Carver among undergraduates (1), who reported a norm of 21.4 + 5.2 among females. However, there was significant overlap in the two groups' standard deviations. Norms for each racial or ethnic group need to be determined, as do norms for adolescents at various stages of development, especially early adolescence. This study was funded in part by Project MCJ-MA 259195 from the Maternal and Child Health Bureau (Title V, Social Security Act), Health Resources and Services Administration, DHHS.
References 1. Scheier MF, Carver CS. Optimism, coping, and health: Assessment and implications of generalized outcome expectancies. Health Psychol 1985;4:219-47.
JOURNAL OF ADOLESCENT HEALTH
Vol. 21, No. 4
2. Scheier MF, Mathews KA, Owens JF, et al. Dispositional optimism and recovery from coronary artery bypass surgery: The beneficial effects on physical and psychological wellbeing. J Personal Social Psychol 1989;57:1024-40. 3. Carver CS, Pozo C, Harris SD, et al. How coping mediates the effect of optimism on distress: A study of women with early stage breast cancer. J Personal Social Psychol 1993;65:375-90. 4. Aspinwall LG, Taylor SE. Modeling cognitive adaptation: A longitudinal investigation of the impact of individual differences and coping on college adjustment and performance. J Personal Social Psychol 1992;63:989-1003. 5. Robbins AS, Spence JT, Clark H. Psychological determinants of health and performance: The tangled web of desireable and undesireable characteristics. J Personal Social Psychol 1991;61: 755-65. 6. Perkins DO, Lesserman J, Murphy C, Evans DL. Psychosocial predictors of high-risk sexual behavior among HIV-negative gay men. AIDS Educ Prevent 1993;5:141-52. 7. Goodman E, Chesney MA, Tipton AC. The relationship of optimism, knowledge, attitudes and beliefs to HIV antibody testing by at-risk female adolescents. Psychosom Med 1995;57: 541-6. 8. Knight J, Goodman E, Pulerwitz T, DuRant R. Reliability of the Problem Oriented Screening Instrument for Teenagers (POSIT) in an adolescent medicine clinic population. Substance Misuse (in press). 9. Winer B. Statistical Issues in Experimental Design, 2nd ed. New York: McGraw-Hill; 1971:287. 10. Koizumi R. Feelings of optimism and pessimism in Japanese students' transition to junior high school. J Early Adolesc 1995;15:412-28.
ADOLESCENT HEALTH BRIEF
Use of the Life Optimism Test Among Adolescents in a Clinical Setting: A Report of Reliability Testing ELIZABETH G O O D M A N , M.D., J O H N R. KNIGHT, M.D., A N D ROBERT H. D u R A N T , Ph.D.
This study examined the consistency and reliability o f the Life Optimism Test (LOT) among patients attending an adolescent medicine clinic. The LOT had good internal consistency (Cronbach's alpha ranging from 0.56 at pretest to 0.76 at posttest) and good 1-week test-retest reliability (intraclass correlation = 0.84). These data support u s e o f the LOT to measure optimism among adolescents. © Society f o r Adolescent Medicine, 1997 KEY WORDS,"
Optimism Adolescents Reliability Although optimism is generally viewed as a positive attribute, this trait has received little systematic evaluation among adolescents. Optimism is defined as the tendency to believe one will experience positive outcomes in life (1). In studies of adults, optimism has been associated with beneficial health effects (2,3). Among college students, higher optimism has been associated with better adjustment to college (4) and higher expected levels of academic achievement (5). However, higher optimism was positively correlated with sexual risk behaviors among human immunodeficiency virus (HIV)-negative homosexual men (6) and less use of HIV testing services among female adolescents engaging in risk behaviors (7). The Life Optimism Test (LOT), the instrument used to measure optimism in these studies, has not From the Division of Adolescent/Young Adult Medicine (E.G., R.H.D.) and the Division of General Pediatrics (J.R.K.), Children's Hospital, Boston, Massachusetts. Address reprint requests to: Elizabeth Goodman, M.D., Children's Hospital, 300 Longwood Avenue, Boston, MA 02115. Manuscript accepted April 12, 1997. 1054-139X/97/$17.00 PII $1054-139X(97)00123-7
been validated among teens. The Generalized Expectancy for Success Scale, another measure of optimism, has been used in a study of Japanese adolescents (10). This measure was developed to measure adults' expectations of obtaining future goals and does not assess optimism as a trait as does the LOT. The LOT is an eight item Likert-type scale, with four filler items (Table 1). The psychometric properties of the LOT were tested on a predominantly white undergraduate college population and were reported to include good convergent and discriminant validity, Cronbach's alpha of 0.76, and 4-week testretest reliability of 0.79 (1). This study examined the internal consistency and one-week test-retest reliability of the LOT in an ethnically diverse sample of adolescent patients to determine its applicability in research with adolescents in an urban medical clinic setting.
Methods Sample Description and Overview This analysis is based on data collected as part of a study of the psychometric properties of two scales: the Problem-Oriented Screening Instrument for Teenagers (POSIT) and the LOT. Analyses of the POSIT scale have been published elsewhere (8). The study took place at an urban, hospital-based adolescent medicine clinic which served both inner-city and suburban youth. Fifteen- to 18-year-old patients who were being seen for well and scheduled sick adolescent visits or for walk-in appointments for non-urgent reasons were eligible to participate. Patients were excluded if they were being seen for acute problems or if their medical provider believed that completing the questionnaire would be too
© Society for Adolescent Medicine, 1997 Published by Elsevier Science Inc., 655 Avenue of the Americas, New York, NY 10010
October 1997
Table 1. Life Optimism Test Scale Items 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11.
In uncertain times, I usually expect the best. It's easy for m e to relax (filler item). If something can go w r o n g for me, it will. I always look on the bright side of things. I'm always optimistic about m y future. I enjoy m y friends a lot (filler item). It's important for m e to keep busy (filler item). I hardly ever expect things to go m y way. Things never work out the way I w a n t them to. I don't get upset too easily (filler item). I'm a believer in the idea that "every cloud has a silver lining." 12. I rarely count on good things h a p p e n i n g to me.
stressful. Based on these criteria, three patients newly diagnosed as pregnant, three patients being seen for anorexia nervosa, and one patient being evaluated for possible sexual assault were excluded. One hundred seventy-three patients agreed to participate. Information on the number of subjects who refused to participate was not kept. Subjects were enrolled by a trained research assistant not involved in the medical care process, who explained the purpose of the study and that the questionnaire would be anonymous. The research assistant obtained informed consent from the patient, who then completed the questionnaire ("pretest LOT"). Ninety percent (156 of 173) provided adequate data for LOT scale construction and comprise the study sample. After completing the questionnaire, subjects made an appointment to return for one week to complete the follow-up questionnaire. Eighty-six subjects (55%) returned for their follow-up appointment, 85 of w h o m provided adequate data for scale construction ("postest LOT"). There was no difference in age, gender, or race between those who completed the postest and those who did not. Subjects received a small gift certificate from a local merchant (i.e., for a slice of pizza) for completing the follow-up questionnaire. The study received approval from the hospital's human subjects committee. The 156 subjects reflected the population served by the clinic, with 71% being female, 17% white, 17% of Hispanic ethnicity, 42% African-American, and 1% Asian. The mean grade was 10.9 + 1.0 (range 10-13). The mean age was 16.3 + 1.1 years.
Statistical Analysis A repeated-measures analysis of variance (ANOVA) was computed on the pretest and posttest LOTs. One-week test-retest reliability was then computed
LIFE OPTIMISM TEST A M O N G ADOLESCENTS
219
from the ANOVA results using Winer's unbiased estimate of the intraclass correlation (9). Internal consistency was computed using Cronbach's alpha. Statistical computations except the intraclass correlation were performed using SPSS for Windows. Means are reported with standard deviations.
Results The mean LOT was 18.8 + 5.3 among: females and 20.9 + 5.4 among males. Because this difference was not statistically significant, males and females were combined for the remaining analyses. The mean LOT score was 19.1 + 4.7 at pretest and 119.3 + 5.4 at posttest. Among those who returned for follow-up, the mean pretest LOT score was 19.2 + .5.2. The mean pretest LOT among those who failed to return for follow-up was 18.9 + 4.1. This difference was not significant. The LOT demonstrated adequate internal consistency. Pretest LOT Cronbach's alpha was 0.56. Item analysis indicated that when one item (Item 1) was deleted ("In uncertain times, I usually expect the best"), the Cronbach's alpha increased to 0.58. Subgroup analyses between those who did and did not return for follow-up revealed that the pattern of answering Item I differed between these groups and contributed significantly to the Cronbach's alpha. Among those who returned for follow-up, Cronbach's alpha on the pretest LOT was 0.64. When Item 1 was deleted, the Cronbach's alpha decreased to 0.60. Among those who did not return :for follow-up, pretest Cronbach's alpha was 0.44. This increased to 0.55 when Item 1 was deleted. On posttest, Cronbach's alpha was 0.76. Item analysis of the posttest LOT indicated that deletion of any item would decrease the consistency. Deletion of Item 1 made a negligible decrease in the Cronbach's alpha (0.0008). The LOT had a good test-retest intraclass correlation of 0.84.
Discussion This study demonstrates that the LOT will reliably measure optimism among mid-adolescents in an adolescent medicine clinic. There was good testretest reliability and internal consistency. The increase in Cronbach's alpha noted between administrations of the instrument suggests that that internal consistency reflects not only properties of the instrument, but also the individual's familiarity with the measure. The changes in internal consistency related to deletion of Item 1 suggest that those who did not
220
GOODMAN ET AL.
complete follow-up were less consistent in how they responded to this item, compared to Items 2-8. Longitudinal studies using this instrument should consider computing the LOT only for those who complete follow-up. The Cronbach's alphas reported here are consistent with that reported by Goodman et al. (0.61) in their sample of 124 predominantly African-American females attending a health maintenance organization (7). The means for females from this sample are also slightly lower than those reported by Scheier and Carver among undergraduates (1), who reported a norm of 21.4 + 5.2 among females. However, there was significant overlap in the two groups' standard deviations. Norms for each racial or ethnic group need to be determined, as do norms for adolescents at various stages of development, especially early adolescence. This study was funded in part by Project MCJ-MA 259195 from the Maternal and Child Health Bureau (Title V, Social Security Act), Health Resources and Services Administration, DHHS.
References 1. Scheier MF, Carver CS. Optimism, coping, and health: Assessment and implications of generalized outcome expectancies. Health Psychol 1985;4:219-47.
JOURNAL OF ADOLESCENT HEALTH
Vol. 21, No. 4
2. Scheier MF, Mathews KA, Owens JF, et al. Dispositional optimism and recovery from coronary artery bypass surgery: The beneficial effects on physical and psychological wellbeing. J Personal Social Psychol 1989;57:1024-40. 3. Carver CS, Pozo C, Harris SD, et al. How coping mediates the effect of optimism on distress: A study of women with early stage breast cancer. J Personal Social Psychol 1993;65:375-90. 4. Aspinwall LG, Taylor SE. Modeling cognitive adaptation: A longitudinal investigation of the impact of individual differences and coping on college adjustment and performance. J Personal Social Psychol 1992;63:989-1003. 5. Robbins AS, Spence JT, Clark H. Psychological determinants of health and performance: The tangled web of desireable and undesireable characteristics. J Personal Social Psychol 1991;61: 755-65. 6. Perkins DO, Lesserman J, Murphy C, Evans DL. Psychosocial predictors of high-risk sexual behavior among HIV-negative gay men. AIDS Educ Prevent 1993;5:141-52. 7. Goodman E, Chesney MA, Tipton AC. The relationship of optimism, knowledge, attitudes and beliefs to HIV antibody testing by at-risk female adolescents. Psychosom Med 1995;57: 541-6. 8. Knight J, Goodman E, Pulerwitz T, DuRant R. Reliability of the Problem Oriented Screening Instrument for Teenagers (POSIT) in an adolescent medicine clinic population. Substance Misuse (in press). 9. Winer B. Statistical Issues in Experimental Design, 2nd ed. New York: McGraw-Hill; 1971:287. 10. Koizumi R. Feelings of optimism and pessimism in Japanese students' transition to junior high school. J Early Adolesc 1995;15:412-28.