Many people warned that the Fight Online Sex Trafficking Act (FOSTA) would endanger the lives of adults who consensually exchange sex for money. Ten months after its passage, CBS San Francisco reported that the city saw a whopping 170 percent "spike in human trafficking" last year. But there are reasons to be wary of the CBS story and the San Francisco Police Department (SFPD) data it relied on.

While ample signs point to negative effects from FOSTA, which made it a federal crime for websites and other online platforms to facilitate prostitution, this probably isn't one of them. What it does illustrate is that increased police attention to the "problem" doesn't equate to more people helped or justice served.

According to a year-end report, SFPD opened 40 sex-trafficking investigations in 2017 and around 108 in 2018—there's the 170 percent spike. But pull back, and it's unclear whether FOSTA, which became law on April 11 last year, is really to blame. In 2014, for instance, SFPD opened 80 sex-trafficking investigations—double the number from 2017. In 2015, the department either worked on 67 or 169 investigations, depending on which of its sources you consult.

That brings us to another important distinction: An investigation means simply that police looked into something and filed a report. It doesn't mean that they found forced or underage prostitution, that arrests were made, or that charges were filed. In 2017, just nine investigations were taken to the San Francisco District Attorney's Office for prosecution, and just one of those cases led to an indictment. In 2016, 10 cases were presented to prosecutors and six led to charges.

Last year, city police and prosecutors ramped up efforts to target human trafficking. Additionally, an increase in street-based prostitution in certain neighborhoods—the inevitable result of FOSTA's targeting of online advertising platforms—meant increased sex-worker visibility. In other words, the level of sex trafficking reported "doesn't necessarily map to prevalence," as Notre Dame law instructor Alex Frell Levy pointed out on Twitter. Indeed, an SFPD spokesperson attributes the spike to an "an increase in awareness and reporting," not an increase in underlying rates.

Nonetheless, a wealth of anecdotal evidence from sex workers, police, health care providers, and others—in the Bay Area and beyond—suggests bad outcomes from government efforts to close online sex-work markets.

At an October 2018 meeting of the city's Task Force on Human Trafficking, "some members shared their perspective on the impact of FOSTA," according to the minutes. "An increase in street-based sex work in the Mission District has been observed. Members from the Police Department shared that they have seen a ripple effect after the [April 6] closure of Backpage and that more sites have popped up on the internet. They said that the demand for sex work has not changed with the law."

In August, SFPD formed a Sex Worker Abatement Unit. Although police have couched recent stings as attempts to stop "pimps" and "traffickers," much of their efforts end up targeting sex workers or their clients. "Arrests have increased dramatically and noticeably, and as a result sex workers who are victims of violence are intimidated and running from police," Rachel West of the U.S. PROStitutes Collective told reporters last December.

The city passed a law in 2017 clarifying that officers shouldn't arrest sex workers reporting crimes, and a bill stating the same has been introduced at the state level. But with police intent on "abating" sex work altogether, these measures likely won't cut it.