Under asymmetric information about sexual history, sexual activity creates externalities. Abstinence by those with few partners perversely increases the average probability of HIV infection in the pool of available partners. Since this increases prevalence among the high activity people who...

A seven-year randomized evaluation suggests education subsidies reduce adolescent girls' dropout, pregnancy, and marriage but not sexually transmitted infection (STI). The government's HIV curriculum, which stresses abstinence until marriage, does not reduce pregnancy or STI. Both programs...

Vaccines exert a positive externality, reducing spread of disease from the consumer to others, providing a rationale for subsidies. We study how optimal subsidies vary with disease characteristics by integrating a standard epidemiological model into a vaccine market with rational economic...

We argue that in pharmaceutical markets, variation in the arrival time of consumer heterogeneity creates differences between a producer's ability to extract consumer surplus with preventives and treatments, potentially distorting R&D decisions. If consumers vary only in disease risk, revenue...