BackgroundA psychometric study of the Family Adaptability and Cohesion Scale (FACES III) has been conducted in Spanish-speaking countries from the perspective of the classical test theory. However, this approach has limitations that affect the psychometric understanding of this scale.ObjectiveAccordingly, this study used the item response theory to investigate the psychometric performance of the items. Furthermore, it evaluated the differential performance of the items for Colombia and Chile.MethodFor this purpose, 518 health science students from both countries participated. Confirmatory Factor Analysis was used.ResultsThe study results revealed that the cohesion and adaptability items presented adequate discrimination and difficulty indices. In addition, items 5, 8, 13, 17, and 19 of cohesion indicated differential functioning between students from both countries, with Chilean students exhibiting a greater discriminatory power. Further, the Colombian group exhibited a greater discriminatory power for item 18 of adaptability.ConclusionsThe study concluded that the items of FACES III indicated adequate psychometric performance in terms of their discriminative capacity and difficulty in Chile and Colombia. C1 [Vilca, Lindsey W.] Univ Norbert Wiener, South Amer Ctr Educ & Res Publ Hlth, Lima, Peru. [Diaz-Narvaez, Victor] Univ Andres Bello, Dent Fac, Res Dept, Santiago, Chile. [Hidalgo, Wilson Pasten; Bakit, Nicolas Van Niekerk; Reyes, Paula Moreno] Univ Atacama, Fac Hlth Sci, Dept Kinesiol, Copiapo, Chile. [Herazo-Beltran, Yaneth; Gauna-Quinonez, Aura] Univ Simon Bolivar, Dept Physiotherapy, Barranquilla, Colombia. [Reyes-Reyes, Alejandro] Univ St Tomas, Fac Social Sci & Commun, Sch Psychol, Concepcion, Chile. [Palacio, Luz Marina Alonso] Univ Norte, Div Ciencias Salud, Barranquilla, Colombia. [Mendoza, Marco Cervantes] Univ Norte, Dept Psicol, Div Human & Ciencias Sociales, Barranquilla, Colombia. C3 Universidad Norbert Wiener; Universidad Andres Bello; Universidad de Atacama; Universidad del Norte Colombia; Universidad del Norte Colombia