This paper assesses the test retest reliability of the Work Ability Index (WAI) in nursing workers. A self-administered questionnaire was applied twice to a group of 80 workers (nurses and nursing aides/assistants) at a public hospital in Rio de Janeiro, Brazil within an interval from seven to fifteen days. The reliability was estimated using quadratic weighted kappa statistics, interclass correlation coefficient (ICC) and the Bland and Altman plot. Eighty-one percent of participants were women aged betweenfrom 22 to 67 years (mean =39.1; SD=10.8 years); 36.3% had completed higher education. The global score of the WAI presented ICC= 0.79 (IC95% 0.67 to 0.86) and weighted kappa=0.69 (CI95% 0.50 to 0.80) for categorical WAI (classified as low, moderate, good and excellent). The quadratic weighted kappa of the WAI items ranged from 0.39 to 0.82 and the Bland and Altman plot did not show a systematic pattern. The agreement between the test and retest measures shows an acceptable degree of reliability, suggesting the adequacy of the assessment process among nursing workers.
Reliability; Work ability; Nursing; Kappa; Interclass Correlation Coefficient (ICC); Bland and Altman graphic