title: Measuring Work Functioning: Validity of a Weighted Composite Work Functioning Approach.
abstract: OBJECTIVE
  To examine the construct validity of a weighted composite work functioning measurement approach.
  
  
  METHODS
  Workers (health-impaired/healthy) (n = 117) completed a composite measure survey that recorded four central work functioning aspects with existing scales: capacity to work, quality of work performance, quantity of work, and recovery from work. Previous derived weights reflecting the relative importance of these aspects of work functioning were used to calculate the composite weighted work functioning score of the workers. Work role functioning, productivity, and quality of life were used for validation. Correlations were calculated and norms applied to examine convergent and divergent construct validity. A t test was conducted and a norm applied to examine discriminative construct validity.
  
  
  RESULTS
  Overall the weighted composite work functioning measure demonstrated construct validity. As predicted, the weighted composite score correlated (p < .001) strongly (r > .60) with work role functioning and productivity (convergent construct validity), and moderately (.30 < r < .60) with physical quality of life and less strongly than work role functioning and productivity with mental quality of life (divergent validity). Further, the weighted composite measure detected that health-impaired workers show with a large effect size (Cohen's d > .80) significantly worse work functioning than healthy workers (discriminative validity).
  
  
  CONCLUSIONS
  The weighted composite work functioning measurement approach takes into account the relative importance of the different work functioning aspects and demonstrated good convergent, fair divergent, and good discriminative construct validity.
authors.affiliation: Coronel Institute of Occupational Health, Academic Medical Center, University of Amsterdam, PO Box 22700, 1100 DE, Amsterdam, The Netherlands.
authors.forename: Edwin J
authors.initials: EJ
authors.lastname: Boezeman
authors.forename: Judith K
authors.initials: JK
authors.lastname: Sluiter
authors.forename: Karen
authors.initials: K
authors.lastname: Nieuwenhuijsen
mesh_terms: D000328:Adult; D004526:Efficiency; D005260:Female; D006801:Humans; D008297:Male; D011788:Quality of Life; D015203:Reproducibility of Results; D014937:Work / Q000592:standards; D014938:Work Capacity Evaluation