Malaria, Productivity and Access to Treatment: Experimental Evidence from Nigeria

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The consequences of ill health for productivity and economic development are presumed to be severe yet the rigorous evidence base for such a linkage is small. Vector borne diseases such as malaria cause direct impacts on the health and indirect impacts on the productivity and income of workers. In previous work, we have estimated statistically significant and large average treatment effects on earnings, labor supply and productivity of a curative malaria treatment using 800 seasonal cane cutting workers at a large sugarcane plantation in Nigeria using a randomized design. To estimate treatment effects, we use individual worker productivity data, derived from the piece rate wage system, which provides data on daily individual worker output and labor supply. A mobile health clinic was established on the plantation and used an exogenously determined ordering of workers to test and treat workers throughout the sugarcane harvest season. Despite large average treatment effects, we estimate only small, but statistically significant intent to treat effects exclusively on labor supply. These results present an explanation for why firms do not provide more extensive testing and treatment for malaria. Due to the small intent to treat labor supply effects, it is likely to be more cost-effective for firms to hire more workers than invest in health services for workers. But the results also present a puzzle as to why workers do not take up preventative or curative treatment for malaria, while the potential gains are large. To better understand under what conditions workers will take up private treatment, we propose to extend our work by offering access to malaria testing and treatment at exogenously varied prices and estimate its effect on take-up and frequency of health care, and their effects on worker productivity. Collecting additional information on workers' social networks and subjective expectations of the risk of malaria infection will also increase the understanding of the determinants of demand for private health care and insurance against illness from malaria. The access to treatment intervention will be offered during the second part of the harvest season. In the first part of the harvest season the study will replicate and extend the previous approach by measuring the effect of treatment on both worker productivity and physical activity. This will provide us with a broader insight of the effect of malaria infection on physical activity in general, and allow us to draw careful inference regarding the potential effects of malaria treatment on other work activities. Workers will be informed at the beginning of the season that they get a free treatment in the first part of the season (randomly allocated) but will need to pay in the second part if they want further access. This combined approach strikes a balance between creating access to treatment for the workers, making sure they realize the benefits of treatment, and respecting real life budget constraints of health care provision.