Psychometric Evaluation of an ICF-Based Instrument to Assess Work Ability in Occupational Health Care

Area of Science:

• Occupational health
• Rehabilitation medicine
• Health informatics

Background:

• Occupational health professionals (OHPs) face challenges in consistent work ability assessments for employees on long-term sick leave due to differing perspectives.
• The International Classification of Functioning, Disability, and Health (ICF)-based Work Ability & Reintegration Description (WARD) instrument was developed to standardize these assessments.

Purpose of the Study:

• To evaluate the psychometric properties of the WARD instrument, focusing on criterion validity and reliability.
• To assess the consistency of WARD-instrument use among OHPs in evaluating work ability.

Main Methods:

• A mixed-methods approach involving a reference standard development using the Modified Delphi method with nine OHPs.
• Independent assessment of 10 case vignettes by 22 OHPs using the WARD instrument.
• Exploration of assessment variation sources through a focus group with eight OHPs.

Main Results:

• Overall agreement with the reference standard ranged from 58.6% to 99.5%, with high agreement (>70%) for 23 out of 29 items.
• Specificity generally exceeded sensitivity, indicating better consistency in excluding irrelevant items.
• Focus groups highlighted the need for context-dependent assessments to aid rehabilitation.

Conclusions:

• The WARD instrument demonstrates promising criterion validity and reliability, particularly for objective physical functioning.
• Assessing complex, context-dependent domains like cognitive function and personal factors remains a challenge for consistent OHP evaluation.
• The WARD instrument may enhance person-centered sick leave guidance by identifying RTW barriers; further real-life validation is recommended.