“HIV and Sexual Behavior Change: Why Not Africa?” by Emily OSTER
University of Chicago
The response of sexual behavior to HIV in Africa is an important input to predicting the path of the epidemic and to focusing prevention efforts. Existing estimates suggest limited behavioral response, but generally fail to take into account possible differences across individuals. A simple model of sexual behavior choice among forward-looking individuals implies that behavioral response should be larger for those with lower non-HIV mortality risks and those who are richer. I estimate behavioral response using a new instrumental variables strategy, instrumenting for HIV prevalence with distance to the origin of the virus. I find low response on average, consistent with existing literature, but larger responses for those who are richer or face lower non-HIV mortality. I also show suggestive evidence, based on a very simple calibration, that the magnitude of behavioral response in Africa is of a similar order of magnitude to that among gay men in the United States once differences in income and life expectancy are taken into account.