A new paper in the American Economic Journal: Economic Policy by Bisschop, Kastoryano, and van der Klaauw looks at the opening and closing of prostitution zones (tippelzones) in 25 Dutch cities.

Our empirical results show that opening a tippelzone reduces sexual abuse and

rape. These results are mainly driven by a 30–40 percent reduction in the first two

years after opening the tippelzone.

For tippelzones with a licensing system, we

additionally find long-term decreases in sexual assaults and a 25 percent decrease

in drug-related crime, which persists in the medium to long run.

Cunningham and Shah studied decriminalization of indoor prostitution in Rhode Island and found very similar results.

We exploit the fact that a Rhode Island District Court

judge unexpectedly decriminalized indoor prostitution in 2003 to provide the first causal estimates

of the impact of decriminalization on the composition of the sex market, rape offenses, and sexually

transmitted infection outcomes. Not surprisingly, we find that decriminalization increased the size

of the indoor market. However, we also find that decriminalization caused both forcible rape offenses

and gonorrhea incidence to decline for the overall population. Our synthetic control model finds 824

fewer reported rape offenses (31 percent decrease) and 1,035 fewer cases of female gonorrhea (39

percent decrease) from 2004 to 2009.

In addition a working paper by Riccardo Ciacci and María Micaela Sviatschi studies prostitution in New York and also finds that prostitution significantly reduces sex crimes such as rape:

We use a unique data set to study the effect of indoor prostitution establishments on sex

crimes. We built a daily panel from January 1, 2004 to June 30, 2012 with the exact location of

police stops for sex crimes and the day of opening and location of indoor prostitution establishments.

We find that indoor prostitution decreases sex crime with no effect on other types

of crime. We argue that the reduction is mostly driven by potential sex offenders that become

customers of indoor prostitution establishments. We also rule out other mechanisms such as

an increase in the number of police officers and a reduction of potential victims in areas where

these businesses opened. In addition, results are robust to different data sources and measures

of sex crimes apart from police stops.

It’s become common to think that rape is about power and not about sex. No doubt. But some of it is about sex. Quoting Ciacci and Sviatschi again:

We find evidence consistent with the fact that potential perpetrators substitute

towards indoor prostitution establishments instead of engaging in sex crimes….This mechanism is in line with a survey of men who had purchased sex from women in London.

About 54% of these men stated that if prostitution did not exist then they would be more

likely to rape women who were not prostitutes. This belief was clearly held by one man who even

stated: “Sometimes you might rape someone: you can go to a prostitute instead” (Farley et al.,

2009).

In short, a wide variety of evidence from different authors, times and places, and experiments shows clearly and credibly that prostitution reduces rape. This finding is of great importance in considering how prostitution should be rationally regulated.