A few years ago, Jevin West told fellow University of Washington professor Carl Bergstrom that he was starting a new course on big data. “Oh yeah,” Bergstrom joked, “I’m starting a course called ‘Calling bullshit on big data.’”

The pair worked together to develop a course, Calling Bullshit, broadening the scope to offer tips on how to detect and disarm spurious appeals to data and science in anything from TED talks to medical papers. The syllabus went viral, and dozens of universities around the world now draw on the UW material. Bergstrom and West reoriented their careers around bullshit detection, wrote a forthcoming book, and in December established a new Center for an Informed Public.

A month later, the novel coronavirus arrived. The professors quickly realized it would be their toughest assignment yet in forensic scatology. The pandemic has added Miracle-Gro to what Bergstrom and West’s course calls the “natural ecology of bullshit.” Human nature and society—particularly online—offer psychological and monetary rewards for attracting attention, regardless of whether information is accurate. That the president of the United States has repeatedly spread untruths about the coronavirus and the government’s response aggravates the situation.

As the virus spreads, Bergstrom and West have been deluged by calls for help checking suspect claims and have helped clean up Covid-19 misinformation on Twitter and elsewhere. What they’ve found offers tips on spotting and avoiding the information hazards of pandemic times—and suggests we will be navigating them for a while.

Last week, Bergstrom, an infectious disease specialist, chased down a viral Twitter thread in which neurologist Scott Mintzer at Thomas Jefferson University in Philadelphia described ICUs in Seattle, 2,800 miles away, flooded with dying patients, citing an unidentified intensivist. It included a claim that doctors were withholding life-saving equipment from overweight patients.

Bergstrom reached out to Seattle health care workers to check on the claims and received many messages refuting them. He also contacted Mintzer, who he says initially defended his posts but later deleted them. “The lesson is to be really questioning of unsourced, second-hand reports when they are the most shocking and dramatic,” Bergstrom says. Mintzer told WIRED, “Disputes about accuracy were not the main reason I took it down."

University of Washington professor Kate Starbird used a database of tweets about Covid-19 to create this chart showing how retweets (blue circles), quotes (orange diamonds), or retweets of quotes (green circles), boosted a tweet sharing inaccurate scientific claims about the novel coronavirus. Courtesy of Kate Starbird

Saturday evening, Bergstrom spent several hours writing a 31-tweet thread debunking a widely shared Medium post by a tech worker who said, based in part on his experience in viral marketing, that officials are overreacting with strict limits on personal movement. Soon after, Medium replaced the post with a message stating that it is “under investigation or was found in violation of the Medium Rules.”