Item analysis of the Grit Assessment Scale: International version in Portuguese language

Grit can be understood as an element of personality, being a positive and non-cognitive human characteristic, composed of two components: perseverance of effort and consistency of interests. Due to its social, professional, and educational impact, grit has become a construct of great interest. Although some instruments have been developed and adapted for its evaluation in different contexts, the absence of measures in Portuguese led to the development of the Grit Assessment Scale – International Version in Portuguese Language (EAGrit-LP), based on samples from Brazil and Portugal. Even though previous studies have investigated some evidence of validity for the instrument, its items had not yet been individually evaluated. Therefore, the objective of the present study was to perform an item analysis, using Item Response Theory. For this purpose, a sample of 1.050 Brazilians and 656 Portuguese individuals responded to the EAGrit-LP (aged between 17 and 71 years old; M = 24.1 years; SD = 9.2). The results showed that all items had appropriate infit and outfit indices, and that items difficulty was, in general, low. Six items displayed differential item functioning (DIF), based on participants’ gender and country of origin. These results can be used to revise the scale and guide the development of more challenging items, as well as to the development of normative tables that are specific to gender and country of origin.