Study Links Craigslist Personal Ads to Increase in New HIV Cases

A new University of Minnesota study that was published in MIS Quarterly links the introduction of Craigslist personal ads to a “15.9 percent increase in reported HIV cases. When mapped at the national level, more than 6,000 HIV cases annually and treatment costs estimated between $62 million and $65.3 million can be linked to the popular website, the authors state.” More from

Postulating that “the ease of seeking sex partners through classified ad sites may promote risky behaviors that increase transmission of STDs,” the researchers reviewed HIV surveillance data from 33 U.S. states between 1999 and 2008 and compared that with the arrival of Craigslist personals in various markets.

After factoring out other explanations for the increases, the investigators concluded that Craigslist likely played a role in a nearly 16 percent rise in HIV cases in those locales.

Jason Chan, assistant professor of information and decision sciences at the Carlson School of Management at the University of Minneapolis and the study’s lead author wrote, “Our analysis suggests that the site entry produces an average of 6,130 to 6,455 cases of HIV infection in the U.S. each year, mapping out to $62 million to $65.3 million dollars in annual treatment costs.”

It’s also worthy of note that the study suggests it was casual hookups—not sex-worker interactions—that prompted the rise. You can browse the paper, titled “Internet’s Dirty Secret: Assessing the Impact of Online Intermediaries on HIV Transmission,” here.