Factorial analysis of the Brazilian-Portuguese version of the Work Ability Index, reproducibility and validity of the single item and the short version for online application

Abstract

BackgroundThe Work Ability Index (WAI) assesses work demands, health status, and physical and mental resources. ObjectivesTo evaluate the measurement properties of the WAI, single-item work ability score (WAS), and short version for online applications. MethodsOne hundred three workers completed the 3 versions of the WAI and the Perceived Stress Scale (PSS-10) questionnaire. The reproducibility and construct validity of the 3 versions of the WAI and their concurrent validity with the PSS-10 were tested. Statistical tests were performed with IBM® SPSS 28.0. ResultsThe test-retest reliability of the WAI, WAS, and WAI short version ranged from good to excellent. The WAI and WAI short version showed excellent internal consistency. The construct validity of the WAS was moderate and positive and it was excellent and positive for the WAI short version. Concurrent validity of the WAI, WAS, and WAI short version was moderate and negative, and item mental resources were strong and negative. Factor analysis reached an acceptable level for all indexes (≥ 0.90). The analysis with two factors reached an acceptable level for all indexes (≥ 0.90) and was the best model. ConclusionThe reliability and construct and concurrent validity of the various versions of the WAI were strong to excellent in online applications. Confirmatory factor analysis demonstrated a new grouping of items for the WAI Brazilian version. However, it is necessary to be careful in the choice due to the distribution model of items in health domains and aspects of work.