Validation of the 10-item Well-being instrument (WiX) in Argentina, Chile, Ecuador, and Peru

Well-being assessment is increasingly relevant for economic evaluations, especially in the health and social care sectors. However, measures like the 10-item Well-being instrument (WiX) have primarily been developed and validated in high-income settings. In Latin America, the need for validated well-being instruments is growing with the interest in expanding the scope of evaluations. This study aimed to evaluate the content and construct validity of the WiX in Argentina, Chile, Ecuador, and Peru, and assessed whether a “Political participation” item would improve validity. The WiX was translated into Spanish, assessed qualitatively through interviews, and quantitatively using an online survey. Following COSMIN guidelines, content validation assessed relevance, comprehensiveness, and comprehensibility, while construct validation examined convergent, structural, and discriminative validity. Eleven interviews with experts and lay people confirmed the relevance, completeness, and clarity of the WiX items. Survey responses from 2,301 participants showed high correlations between WiX scores and other well-being measures. Exploratory factor analysis confirmed that the WiX captures a broader construct than health-related quality of life, and WiX scores varied as expected across age groups, employment status, partnership status, financial situation, and health status. Finally, adding a “Political participation” item did not enhance validity. In conclusion, the WiX appears to be a valid tool for assessing subjective well-being in these four countries and, therefore, useful for economic evaluations. Given the importance of well-being as a policy endpoint, this validation is an empirical contribution for intervention design, evaluation and monitoring within and across sectors in the Latin American context.