Wood, A. M., Maltby, J., Stewart, N., & Joseph, S. (2008). Conceptualizing gratitude and appreciation as a unitary personality trait. Personality and Individual Differences, 44, 619-630.

Gratitude and appreciation are currently measured using three self-report instruments, the GQ6 (1 scale), the Appreciation Scale, (8 scales) and the GRAT (3 scales). Two studies were conducted to test how these three instruments are interrelated, whether they exist under the same higher order factor or factors, and whether gratitude and appreciation is a single or multi-factorial construct. In Study 1 (N = 206) all 12 scales were subjected to an exploratory factor analysis. Both parallel analysis and the minimum average partial method indicated a clear one factor solution. In Study 2 (N = 389) multigroup confirmatory factor analysis supported the one factor structure, demonstrated the invariance of this structure across gender, and ruled out the confounding effect of socially desirable responding. We conclude gratitude and appreciation are a single-factor personality trait. We suggest integration of gratitude and appreciation literatures and provide a clearer conceptualization of gratitude.