Willingness-to-pay for schistosomiasis-related health outcomes in Kenya.

Cost-benefit analysis (CBA) provides a framework for identifying, quantifying, and valuing in monetary terms all the important costs and consequences to society of competing disease interventions. Thus, CBA requires that impacts of schistosomiasis interventions on beneficiaries'health be valued in monetary terms Economic theory requires the use of the willingness to pay (WTP) approach in valuation of changes in health as a result of intervention. It is the only approach which is consistent with the potential Pareto improvement principle, and hence, consistent with CBA. The present study developed a health outcome measure and tested its operational feasibility. Contingent valuation for certain return to normal health from various health states, and for remaining in one's current health state were elicited through direct interview of randomly selected rice farmers, teachers, and health personnel in Kenya. The WTP to avoid risk of advancing to the next more severe state, seemed to be higher than WTP for a return to normal health. Generally, there was a significant difference between the average WTP values of farmers, teachers and health personnel populations. The gender and occupation variable coefficients were positive and highly significant in all regressions. The coefficients of the other explanatory variables were generally not statistically significant, indicating that medical expenses, anxiety cost, loss of earnings, and loss of work time, implied in various health states descriptions did not have significant effect on respondents expressed WTP values. The latter finding shows that there is need for more research to identify the other (besides gender and occupation) determinants of expressed WTP values in Africa. This study has demonstrated that it is possible to elicit coherent WTP values from economically under-developed countries. Further empirical work is clearly needed to at least address the validity and reliability of the contingent valuation approach and its measurements in Africa.