Measurement properties of subscales in the work environment impact questionnaire (WEIQ)

Abstract Work ability arises from interactions between individuals, work tasks, and the work environment. Valid instruments for assessing self-perceived work ability are essential to reduce sick leave and optimize productivity. The Work Environment Impact Questionnaire (WEIQ) assesses key workplace factors across four subscales: Physical and Organizational Prerequisites, Work Tasks, Social Relations, and Motivational Aspects. The purpose of this study was to assess the measurement properties of the WEIQ subscales. Rasch analysis was conducted on data from 288 respondents representing three work settings: assisted living, vocational rehabilitation, and a research institute. All subscales showed good targeting and no disordered thresholds but exhibited issues with item fit, local dependency (LD), and/or differential item functioning (DIF). In Work Tasks , LD was identified in four item pairs; after removing one item and creating testlets, the refined scale showed no misfit, DIF, or LD and supported unidimensionality. In Motivational Aspects , three misfitting items and three LD pairs were identified; one item was removed and two testlets were created, resulting in acceptable model fit. Physical and Organizational Prerequisites showed one misfitting item, LD in two item pairs, and DIF in two items; testlets, including one split by workplace, resolved these issues. In Social Relations , misfit, DIF, and LD were identified; two items were removed, testlets were formed, and one DIF item was retained. Across refined subscales, person separation indices ranged from 0.63 to 0.74. The final WEIQ comprised 29 items. Through item removal, testlet formation, and item splitting, acceptable measurement properties and unidimensionality were achieved, supporting the use of common scales across workplaces while allowing for setting-specific differences.