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.
Symptom Severity Work Productivity Auranofin General Health Perception Activity Impairment
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.
This is a preview of subscription content, log in to check access.
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, 1986PubMedCrossRefGoogle 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, 1986CrossRefGoogle 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, 1980CrossRefGoogle Scholar
Guyatt GH, Walter S, Norman G. Measuring change over time: assessing the usefulness of evaluative instruments. Journal of Chronic Diseases 4: 171–178, 1987aCrossRefGoogle 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, 1987bCrossRefGoogle Scholar
Kruskall WH, Wallis WA. Use of ranks in one-criterion analysis of variance. Journal of the American Statistical Association 47: 583–621, 1952CrossRefGoogle 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, 1992PubMedGoogle 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, 1986PubMedGoogle Scholar
Robins LN. Cross-cultural differences in psychiatric disorders. American Journal of Public Health 79: 1479–1480, 1989PubMedCrossRefGoogle 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, 1988PubMedCrossRefGoogle Scholar