The Gratitude Resentment and Appreciation Test-Revised Short (GRAT-RS): A Multidimensional Item Response Theory Analysis in Italian Workers.

Gratitude is a promising resource from a healthy organizational perspective. It is related to many positive outcomes at work. The Gratitude Resentment and Appreciation Test-Revised Short (GRAT-RS) is the most widely used self-report questionnaire to detect gratitude. The present study examined GRAT-RS (the Italian version) by implementing multidimensional item response theory (MIRT) analyses to explore its psychometric properties. The participants were 537 Italian workers. Confirmatory factor analyses (CFA) of the GRAT-RS and MIRT analyses using the Grade Response Model were run. The MIRT discrimination and MIRT difficulty parameters were calculated. A test information function (TIF) and measure of reliability associated with (TIF) scores were also implemented. CFA highlighted that a bifactor model showed the best fit. Hence, MIRT analyses were carried out by implementing a bifactor model. The MIRT bifactor structure showed a good data fit with discrimination parameters ranging from good to excellent and adequate reliability. The good psychometric properties of GRAT-RS were confirmed, highlighting the questionnaire as a reliable tool to measure gratitude in Italian workers.