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The Validity and Reproducibility of a Work Productivity and Activity Impairment Instrument

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Summary

The construct validity of a quantitative work productivity and activity impairment (WPAI) measure of health outcomes was tested for use in clinical trials, along with its reproducibility when administered by 2 different methods. 106 employed individuals affected by a health problem were randomised to receive either 2 self-administered questionnaires (self administration) or one self-administered questionnaire followed by a telephone interview (interviewer administration). Construct validity of the WPAI measures of time missed from work, impairment of work and regular activities due to overall health and symptoms, were assessed relative to measures of general health perceptions, role (physical), role (emotional), pain, symptom severity and global measures of work and interference with regular activity. Multivariate linear regression models were used to explain the variance in work productivity and regular activity by validation measures. Data generated by interviewer-administration of the WPAI had higher construct validity and fewer omissions than that obtained by self-administration of the instrument. All measures of work productivity and activity impairment were positively correlated with measures which had proven construct validity. These validation measures explained 54 to 64% of variance (p < 0.0001) in productivity and activity impairment variables of the WPAI. Overall work productivity (health and symptom) was significantly related to general health perceptions and the global measures of interference with regular activity. The self-administered questionnaire had adequate reproducibility but less construct validity than interviewer administration. Both administration methods of the WPAI warrant further evaluation as a measure of morbidity.

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References

  • Bombardier C, Ware J, Russell IJ, Larson M, Chalmers A, et al. Auranofin therapy and quality of lift in patients with rheumatoid arthritis. American Journal of Medicine 81: 565–578, 1986

    Article  PubMed  CAS  Google Scholar 

  • Croog SH, Levine S, Testa MA, Brown B, Bulpitt CJ, et al. The effects of antihypertensive therapy un the quality of life. New England Journal of Medicine 114: 1657–1664, 1986

    Article  Google Scholar 

  • Freund DA, Dittus RS. Principles of pharmacoeconomic analysis of drug therapy. PharmacoEconomics 1: 20–32, 1992

    Article  PubMed  CAS  Google Scholar 

  • Gilson BS, Erickson D, Chavez CT, Bobbitt RA, Bergner M, et al. A Chicano version of the Sickness Impact Profile (SIP). Culture Medicine Psychiatry 4: 137–150, 1980

    Article  CAS  Google Scholar 

  • Guyatt GH, Walter S, Norman G. Measuring change over time: assessing the usefulness of evaluative instruments. Journal of Chronic Diseases 4: 171–178, 1987a

    Article  Google Scholar 

  • Guyatt GH, Deyo RA, Charlson M, Levine MN, Mitchell A. Responsiveness and validity in health status measurement: a clarification. Journal of Clinical Epidemiology 42: 403–408, 1987b

    Article  Google Scholar 

  • Kruskall WH, Wallis WA. Use of ranks in one-criterion analysis of variance. Journal of the American Statistical Association 47: 583–621, 1952

    Article  Google Scholar 

  • Laupacis A, Feeney D, Detsky AS, Tugwell PX. How attractive does a new technology have to he to warrant adoption and utilization? Tentative guidelines for using clinical and economic evaluations. Canadian Medical Association Journal 146: 473–481, 1992

    PubMed  CAS  Google Scholar 

  • Lipscomb J. Time preference for health in cost-effectiveness analysis. Medical Care 27: S233–S248, 1989

    Article  PubMed  CAS  Google Scholar 

  • O’Toole BI, Battistutta D, Long A, Crouch K. A comparison of costs and data quality of three health survey methods: mail, telephone and personal home interview. American Journal of Epidemiology 124: 317–328, 1986

    PubMed  Google Scholar 

  • Robins LN. Cross-cultural differences in psychiatric disorders. American Journal of Public Health 79: 1479–1480, 1989

    Article  PubMed  CAS  Google Scholar 

  • Stewart AL, Hays RD, Ware JE. The MOS Short-form General Health Survey: reliabilitv and validity in a patient population. Medical Care 26: 724–715, 1988

    Article  PubMed  CAS  Google Scholar 

  • Ware JE, Sherbourne CD. The MOS 36-item short-form health survey (SF-36). Medical Care 30: 473–483, 1992

    Article  PubMed  Google Scholar 

  • Wilber BJ. Statistical principles in experimental design. 2nd ed., McGraw-Hill, New York, 206–207, 1971

    Google Scholar 

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Reilly, M.C., Zbrozek, A.S. & Dukes, E.M. The Validity and Reproducibility of a Work Productivity and Activity Impairment Instrument. PharmacoEconomics 4, 353–365 (1993). https://doi.org/10.2165/00019053-199304050-00006

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