Demonstrating bias and improved inference for stoves’ health benefits
Many studies associate health risks with household air pollution from biomass fuels and stoves. Evaluations of stove improvements can suffer from bias because they rarely address health relevant differences between the households who get improvements and those who do not. Health-relevant factors (age, wealth, kitchen ventilation) do in fact differ considerably between the households with stove improvements and those without. We study the resulting bias in estimates of cleaner-stove impacts using a self-reported Physical Component Summary (PCS). Typical stoves-literature regressions with little control for non-stove factors suggest no benefits from a cleaner-fuel stove relative to a traditional biomass stove. Yet increasing controls raises the impact estimates. Our PSM estimates address the differences in health-relevant factors using ‘apples to apples’ comparisons between those with improved stoves and ‘similar’ households. This generates higher estimates of clean-stove benefits, which are on the order of one half the standard deviation of the PCS outcome.