A Psychometric Evaluation of the Revised Optimism-Pessimism Scale of the MMPI-2
The present study tested the psychometric properties of the Revised Optimism-Pessimism Scale (PSM-R) of the MMPI-2. This scale purportedly measures the respondent's explanatory style on a dimension of optimism and pessimism. Participants included 92 college undergraduates and 2,729 participants from archived outpatient data. The PSM-R is a reliable measure, based on test-retest reliability and internal consistency. However, the construct validity of the measure is questionable. Evaluation of the PSM-R items suggests that the items are not all related to the optimism-pessimism construct. In addition, convergent validity of the PSM-R was assessed using measures of attributional style, dispositional optimism, hope, depression, neuroticism, extraversion, and positive and negative affect. Discriminant validity was assessed using measures of social desirability and self-consciousness. The PSM-R was significantly correlated with all of these validity measures, except attributional style. The pattern of results with these measures and the PSM-R resembled the results of the dispositional optimism measure, rather than that of attributional style. Results from the principal components analysis suggest that the PSM-R does not contain a single factor of optimism-pessimism, but rather contains several factors, some of which are unrelated to the construct of optimism-pessimism. The extracted principal factor is a more pure form of optimism-pessimism, based upon evaluation of the items within the factor, and the correlations between this factor and the other measures of optimism-pessimism. The extracted principal factor appears to resemble dispositional optimism-pessimism rather than explanatory style optimism-pessimism. Current findings suggest that the PSM-R is not accurately measuring what it claims, and use of the measure is questionable as psychometric research on the measure continues.