Italian adaptation and validation of the International Cognitive Ability Resource 16 sample test

The International Cognitive Ability Resource 16 (ICAR-16) is a public-domain measure of cognitive ability. To date, no Italian validation exists. We translated and validated the ICAR-16 in a sample of 486 Italian adults (66.4% female), who completed the ICAR-16 and the long version of the Cognitive Reflection Test (CRT-Long) online. Confirmatory factor analyses supported a second-order latent variable (SOLV) structure (CFI = 0.98; TLI = 0.98). The ICAR-16 showed strong associations with the CRT-Long at both the observed and latent levels, providing partial evidence of convergent validity. Internal consistency reliability was adequate. Measurement invariance analyses supported partial strong second-order factor invariance across sexes, indicating a largely comparable higher-order structure despite sex differences in the intercepts of three first-order cognitive domains. Differential Item Functioning (DIF) analysis provided evidence of uniform DIF for only one item (MR47), indicating a consistent difference in item responses across sexes at comparable total score levels. Overall, these findings support the Italian ICAR-16 as a reliable, freely available instrument for cognitive assessment in research.