Private Choices and Public Health.

• Author: Davidson, Audrey B.

This book presents the first full-scale economic analysis of the AIDS epidemic, providing a fresh perspective on the crisis and offering dramatically different predictions and conclusions from the traditional epidemiological approach to the AIDS crisis. The authors systematically compare and contrast the economic and epidemiological models throughout the book, using economic analysis to determine factors impacting the demand for risky sex, defined as sex without a condom, and more importantly the spread of the epidemic. Philipson and Posner aim to increase understanding of AIDS policies by analyzing behavioral response to the existing (and proposed or hypothetical) policies as well as the success of current policy. Some of the factors identified for analysis include voluntary and mandatory AIDS testing, an individual's probability of infection, as well as government intervention. Because new issues surrounding AIDS appear regularly, the authors present this study as a starting point for economic analysis. Regardless, the book presents a well-constructed analysis with enough variety to appeal to and challenge every reader. Further, it is not technical, perhaps in the hope that policymakers, health professionals, and epidemiologists will recognize that economics (or economic epidemiology) can improve predictions and prescriptions, not only with respect to AIDS, but rather for communicable disease in general.

The first chapter of the book contains the economic model developed by the authors for analyzing risky sexual behavior. Its participants are treated as rational, much the same as in other nonmarket situations. One of the primary distinctions (and criticisms) from the epidemiological models is that these models assume random sorting of sexual partners while in the economic framework sexual partners sort by infection probabilities. Further, the economic approach treats sex as a trade where meeting is random, but the decision to have sex is not. One's willingness to engage in unsafe sex is an increasing function of the probability of being infected and a decreasing function of the likelihood that one's partner is infected. Because male to female transmission is more likely than the converse, it is predicted that prostitutes will prefer safe sex. However, if the prostitute is already infected it is expected that the supply of risky sex might actually increase. The authors also expect that as the incidence of the disease increases, bisexual...