A critical examination of the reliability and validity of the SZTPI-15 in British, American and Australian samples

Abstract As an individual difference variable assessing the extent to which attitudes towards past, present and future influence behavior, time perspective is a potentially useful construct. However, its development and utility has been compromised by measurement issues. Recently, a short form of the Zimbardo Time Perspective Inventory (ZTPI), the SZTPI-15 has been suggested to yield valid and reliable scores. Using three independent samples from America, Australia, and the United Kingdom, the present study tested the psychometric properties of SZPTI-15 scores. Confirmatory factor analyses did not support the 5-factor structure and internal consistency estimates for four of the subscales were low. Fit indices obtained from exploratory structural equation modeling were better, suggesting that permitting items to load on multiple factors improved model fit. Correlations with variables shown to be related to ZTPI factors broadly supported the concurrent validity of the SZTPI-15. Results suggest that further psychometric examination of SZTPI-15 scores is required.