Factor structure and criterion validity of original and short versions of the Negative and Positive Affect Scale (NAPAS)

- Results supported the factor structure, reliability, and criterion validity of the NAPAS.
- A 10-item version of the NAPAS was developed.
- Psychometric qualities of the short version was as good as those of the original version.
- Exploratory structural equation modeling proved to be an effective method.

This study investigated factor structure, reliability, and criterion validity of the original 12-item version as well as an abbreviated 10-item version of Mroczek and Kolarz' Negative and Positive Affect Scale (NAPAS). The sample (N = 2718) was drawn from the third wave of the National Study of Midlife in the United States (MIDUS III). Confirmatory Factor Analysis (CFA) and Exploratory Structural Equation Modeling (ESEM) were used to analyze the data. The 12-item version of the scale demonstrated acceptable psychometric properties. Equally good model fit and reliability and identical criterion correlations were also found for the 10-item version of the scale. This suggests that scale shortening did not have any adverse psychometric effects. ESEM produced slightly better fit and considerably lower factor correlations, and thus was considered superior to CFA in the context of this study. Overall, these results indicate that both versions of the NAPAS show evidence of acceptable psychometric quality. Implications of the results and avenues for future research are discussed.