Validity of the Capacity to Work Index: Development of an Instrument to Measure Work Capacity in Relation to Depression and Anxiety in the General Working Population.

The field test analysed only 51 unique participants, and the authors state this was smaller than anticipated and reduced statistical strength. The sample was mainly female nurses in Swedish hospital departments, so it may not represent other occupations, countries, or welfare systems. Test-retest reliability could not be properly assessed because only 19 of 70 employees completed both questionnaires. The authors did not remove items that did not fit the main pattern in this initial field test because the sample was small and the professional group was homogeneous. The index has not been tested for external validity, cut-off levels, or prediction of sickness absence. People with lived experience of common mental disorders were not included in the early item development phase.

Funding was from Forskningsrådet om Hälsa, Arbetsliv och Välfärd and the University of Gothenburg. No competing-interest statement is provided in the supplied text.

Do not treat the C2WI as a validated clinical tool for return-to-work decisions. The initial field test analysed 51 Swedish health care professionals, mainly nurses, and the authors state that larger and more diverse samples are needed. The correlations with wellbeing and workability do not show that the index predicts sickness absence.