Productivity measurement: An empirical analysis of QALY, human capital, and friction cost methodologies.

摘要

Dissention exists among health economists regarding the measurement and inclusion of productivity costs in a cost-effectiveness analysis. Productivity costs may be measured monetarily, and included in the numerator of a cost-effectiveness ratio, or they may be captured by quality adjusted life years (QALYs), in the denominator of the cost effectiveness ratio. The first objective of this study was to investigate the extent to which changes in productivity costs are explained by changes in QALYs. If productivity costs are measured monetarily, the human capital method or the friction cost method may be applied. The second study objective was to examine the difference between productivity cost estimates obtained with the human capital method and the friction cost method. The selected target sample for the study was informal caregivers of the elderly whose carereceivers were utilizing adult day services. And, the third study objective was to evaluate potential determinants of caregiver outcomes, including quality of life and productivity costs. An observational panel study, with two survey waves, was used to collect data. Surveys were administered in face-to-face interviews to a convenience sample of 102 informal caregivers of the elderly. Results indicated that changes in QALYs did not account for any of the variance in changes in certain productivity cost components, including absence from paid labor, reduced productivity during paid labor, and lost leisure. However, changes in QALYs did account for ten percent of the variance in changes in lost unpaid labor (F = 8.67, P 0.01). Friction cost estimates were found to be significantly less than human capital estimates in both the first and second waves of the study (t = 6.96, P 0.01, t = 6.47, P 0.01). Caregiver outcomes were found to be stable over time. The results of the study imply that most productivity costs should be valued monetarily and included in the numerator of a cost-effectiveness ratio. And, if the friction cost method is used, rather than the human capital method, lower estimates of productivity costs will be obtained.