Valuing malaria morbidity: results from a global meta-analysis

The risk of malaria transmission worldwide is expected to increase with climate change. In order to estimate the welfare implications, we analyse the factors that explain willingness to pay to avoid malaria morbidity using a meta-analysis. We fail to replicate a previous meta-analysis, despite using a near-identical dataset. Thus, this paper outlines a more robust approach to analysing such data. We compare multiple regression models via a cross-validation exercise to assess best fit, the first in the meta-analysis literature to do so. Weighted random effects gives best fit. Confirming previous studies, we find that revealed preferences are significantly lower than stated preferences; and that there is no significant difference in the willingness to pay for policies that prevent (pre-morbidity) or treat malaria (post-morbidity). We add two new results to the morbidity literature: (1) Age has a non-linear impact on mean willingness to pay and (2) willingness to pay decreases if malaria policies target communities instead of individual households.