title: Validity and test-retest reliability of an at-work production loss instrument.
abstract: BACKGROUND
  Besides causing ill health, a poor work environment may contribute to production loss. Production loss assessment instruments emphasize health-related consequences but there is no instrument to measure reduced work performance related to the work environment.
  
  
  OBJECTIVE
  To examine convergent validity and test-retest reliability of health-related production loss (HRPL) and work environment-related production loss (WRPL) against a valid comparable instrument, the Health and Work Performance Questionnaire (HPQ).
  
  
  METHODS
  Cross-sectional study of employees, not on sick leave, who were asked to self-rate their work performance and production losses. Using the Pearson correlation and Bland and Altman's Test of Agreement, convergent validity was examined. Subgroup analyses were performed for employees recording problem-specific reduced work performance. Consistency of pairs of HRPL and WRPL for samples responding to both assessments was expressed using Intraclass Correlation Coefficient (ICC) and tests of repeatability.
  
  
  RESULTS
  A total of 88 employees participated and 44 responded to both assessments. Test of agreement between measurements estimates a mean difference of 0.34 for HRPL and -0.03 for WRPL compared with work performance. This indicates that the production loss questions are valid and moderately associated with work performance for the total sample and subgroups. ICC for paired HRPL assessments was 0.90 and 0.91 for WRPL, i.e. the test-retest reliability was good and suggests stability in the instrument.
  
  
  CONCLUSIONS
  HRPL and WRPL can be used to measure production loss due to health-related and work environment-related problems. These results may have implications for advancing methods of assessing production loss, which represents an important cost to employers.
authors.affiliation: Department of Environmental Medicine, Unit of Intervention and Implementation Research, Karolinska Institutet, SE-171 77 Stockholm, Sweden. emmanuel.aboagye@ki.se.
authors.forename: E
authors.initials: E
authors.lastname: Aboagye
authors.affiliation: Department of Environmental Medicine, Unit of Intervention and Implementation Research, Karolinska Institutet, SE-171 77 Stockholm, Sweden.
authors.forename: I
authors.initials: I
authors.lastname: Jensen
authors.affiliation: Department of Environmental Medicine, Unit of Intervention and Implementation Research, Karolinska Institutet, SE-171 77 Stockholm, Sweden.
authors.forename: G
authors.initials: G
authors.lastname: Bergström
authors.affiliation: Department of Environmental Medicine, Unit of Intervention and Implementation Research, Karolinska Institutet, SE-171 77 Stockholm, Sweden.
authors.forename: J
authors.initials: J
authors.lastname: Hagberg
authors.affiliation: Department of Environmental Medicine, Unit of Intervention and Implementation Research, Karolinska Institutet, SE-171 77 Stockholm, Sweden.
authors.forename: I
authors.initials: I
authors.lastname: Axén
authors.affiliation: Department of Environmental Medicine, Unit of Intervention and Implementation Research, Karolinska Institutet, SE-171 77 Stockholm, Sweden.
authors.forename: M
authors.initials: M
authors.lastname: Lohela-Karlsson
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D003430:Cross-Sectional Studies; D004467:Economics / Q000639:trends; D004777:Environment; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D011795:Surveys and Questionnaires; D000066477:Work Performance / Q000592:standards*
keywords: Measurement methods; occupational medicine; production loss assessment; work performance.