Factorial validity and item response theory analysis of the Gratitude Questionnaire in an Italian sample

The aim of this paper is to assess the diversified behaviors of the Gratitude Questionnaire (GQ-6) items. After providing evidence on the monofactorial structure of the GQ-6 in the Italian context (pilot study), we examined the performance of the questionnaire (main study) relying on item response theory (IRT). Results prove that the sixth item produces a lower discrimination parameter and scarcer infor-mation compared to the other items, while the opposite happens for the first two items. The test infor-mation function shows that the GQ-6 better captures respondents’ gratitude when they are in low to median positions of the trait, compared to higher values of the latent trait. Our findings suggest that the sixth item may be discarded from the GQ-6 in case of time constraints in the research design, and that there might be a response tendency toward the upper response options.