Study Suggests Craigslist Ads Increase HIV Prevalence

More than 6000 HIV cases in the United States annually can be traced to Craigslist’s personals ad sections, according to a study published in the December 2014 edition of MIS Quarterly.

For their research, titled “Internet’s Dirty Secret: Assessing the Impact of Online Intermediaries on HIV Transmission,” a pair of investigators analyzed data from 33 US states over a 10-year period from 1999 to 2008.

After conducting exams to eliminate other potential drivers of HIV trends, such as increased testing for sexually transmitted diseases (STDs), the researchers found that Craigslist’s personals sections—not escort service ads—were related to a 15.9% increase in HIV prevalence. The analysis also suggested that the classified ad site’s entry produces 6130 to 6455 HIV cases in the United States each year, with related treatment costs estimated at $62 million to $65.3 million annually.

"Our study results suggest that there is a new social route of HIV transmission that is taking place in this digital era," said co-author Jason Chan, assistant professor of Information and Decision Sciences at the University of Minnesota’s Carlson School of Management, in a press release. "Health care practitioners and policymakers have to look more closely at online platforms to assess how its usage may facilitate the spread of HIV and STDs across the country."

Chan also believes that his research provides health care professionals with insight into reducing disease transmission through classified ads.

"I actually think that the creators of Craigslist had no intent of harming society. They came in with good intentions,” Chan said. “At the same time, they did not anticipate that users could use the features in an unexpected way with unintended consequences."