Prostitution is a gender issue. Of the total arrests for prostitution in the United States in each year, 70 percent are female prostitutes, 20 percent are either male prostitutes or pimps, and the remaining 10 percent are prostitutes' clients. Since the 1960s, fighting prostitution has been a key target of many American policy interventions. The first "reverse sting" operation to catch prostitutes' clients took place in Nashville, Tennessee, in 1964. Ten years later, St. Petersburg, Florida, spent large financial resources on arresting male customers. In the same year, Eugene, Oregon, started the first shaming campaign in which names or photos of prostitutes' clients were publicized. Likewise, in 1995 San Francisco opened the first school to reeducate arrested sex buyers. The vast majority of these policies attempted to fight prostitution activities by reducing the demand.
I explore the effect of a seemingly unrelated policy on prostitution activities—namely, the approval of unilateral divorce laws in several U.S. states. Although the link between divorce regimes and prostitution may look weak at first sight, there are several channels through which such a relationship could be established. For example, because unilateral divorce law alters the bargaining position of partners within married couples relative to more rigid divorce regimes in which mutual consent is required, introducing such a divorce law could impinge on prostitution via downward shifts in demand and supply. On the one hand, it could be argued that those married men who are clients of prostitutes become more reluctant to purchase such services because their wives could dissolve their marriage more easily under unilateral divorce. As a result, this change in clients' behavior would translate into a reduction in the demand for prostitution. On the other hand, the threat of unilateral divorce may improve the condition of married women, and therefore make marriage a more attractive option, leading to a fall in the supply of prostitution. In either of these two cases, enacting unilateral divorce laws reduces the amount of prostitution in equilibrium.
By the same token, one could think of alternative mechanisms that instead imply an increase in the amount of prostitution. For instance, it could be argued that unilateral divorce laws are likely to increase the number of divorces in the short run and therefore lead to a rise in the share of single people in the population. To the extent that single men demand more prostitution services than do married men, and insofar as single women supply more prostitution services than do married women, these two forces jointly could lead to a larger amount of prostitution in equilibrium.
I address this issue by exploiting a quasi-natural experiment provided by differences in the timing of implementation of unilateral divorce laws across U.S. states. Such differences enable one to identify the potential causal effect of such laws on arrests of female prostitutes. To implement the approach I combine two sources of data: the month in which unilateral divorce laws become effective in each U.S. state and information on criminal arrests drawn from the agency-level Uniform Crime Reporting database. The evidence relies on the plausible identification assumption that the month in which unilateral divorce laws became effective in each state was correlated neither with any crime pattern nor in particular with any prostitution pattern.
My main finding is that unilateral divorce laws reduce arrests for female prostitution by roughly 10.9 percent. This reduction takes place in the first year after the implementation of the law. Since around 60,000 female prostitutes are arrested in the United States on average each year, the estimate implies a reduction of 6,540 women arrested for prostitution during the year when unilateral divorce laws become effective. This decrease yields a reduction of about $16.4 million in policing and prostitution control costs for American taxpayers. As for the decrease in the overall number of female prostitutes, one can make a guess by using information drawn from the French, anti-prostitution Scelles Foundation, which reports about 1 million prostitutes in the United States during the 2000s. Using such a figure and our estimated effect, a simple back-of-the-envelope calculation points out that unilateral divorce laws could have led to 109,000 fewer prostitutes.
Next, I consider the potential mechanisms that could be driving the results. These mechanisms range from a general decline in the number of arrests for all sorts of crimes to changes in both the demand and supply of prostitution. First, I explore if unilateral divorce laws led to a general reduction in arrests for crimes not connected to prostitution per se. Using data on women arrested for robberies, drug crimes and use, and vandalism—three crimes with higher frequency than prostitution—I find that these alternative crimes are not affected by the implementation of unilateral divorce laws.
Second, I examine whether unilateral divorce changed the demand for prostitution. Three separate data sets are used to capture different features of such demand. In particular, data on the number of internet searches of the words "prostitute" and "prostitution" are used to proxy online demand for prostitution; panel-survey data are used to analyze if men's views toward prostitution change after the men get divorced; and data on the number of unmarried men are used to proxy the demand for prostitution by unmarried men. I find no empirical support for the notion that shifts in the demand for prostitution were caused by unilateral divorce laws.
Finally, I look at supply-driven mechanisms stemming from changes in the value of marriage as an outside option to prostitution. In particular, I focus on a potential increase in wages and improvement of conditions in marriage for wives that result from the wives' higher bargaining power when unilateral divorce laws are passed. Using data on the real average wage of wives across U.S. states, I do not find empirical evidence to support that unilateral divorce laws affect wives' real wages. Then, I analyze whether there is evidence that unilateral divorce laws improve wives' conditions in marriage. If this were the case, it seems plausible to conjecture that only female prostitutes of marriage age would exit prostitution since they would be the main recipients of an improvement in wives' welfare. To test this hypothesis, I split the data on arrested female prostitutes into different age groups and find that female prostitutes of marriage age are the main driver of the estimated reduction in female prostitution arrests.
In summary, the mechanism that best explains the 10.9 percent decrease in prostitution is one in which unilateral divorce increases the option value of getting married by improving wives' conditions in marriage. As a result, the opportunity cost of becoming a female prostitute increases, and the supply of prostitution declines. To the best of my knowledge, this is the first empirical research to show that better conditions for wives in marriage lead to a reduction in prostitution. Thus, policymakers that want to decrease prostitution might do so by implementing policies that improve the conditions of wives in marriage.
This research brief is based on Riccardo Ciacci, "The Effect of Unilateral Divorce on Prostitution: Evidence from Divorce Laws in U.S. States," January 25, 2018.