Much in the same way that Twitter can help seismologists track earthquakes in five seconds flat, the ubiquity of Yelp and the viral nature of some of its reviews can be instrumental in not only detecting illnesses early, but also identifying potential patients who will need medical care down the line. In a recent example, Yelp user Pauline A. wrote a review of the Mariscos San Juan #3 restaurant, dated Oct. 18. “PLEASE DO NOT EAT HERE!!!!” she wrote. “My sister-in-law … and brother-in-law along with his parents ate here Friday night and all four of them ended up in the hospital with food poisoning!!!”
Later that day, that very restaurant was shut down by Santa Clara County Public Health Department, and just two days later, officials announced that over 80 patrons of the restaurant had become severely ill, with 12 going into intensive care units.
The use of Yelp in tracking food poisoning cases isn’t a novel notion — back in 2014, New York’s Department of Health and Mental Hygiene partnered with researchers from Columbia University and Yelp to scan 294,000 reviews of restaurants in the city between July 1, 2012, and March 13, 2013, for reports of food-borne diseases. By flagging for words like “sick,” “vomit,” “diarrhea” and “food poisoning,” the team ultimately found some 900 cases (previously unreported to public health officials) that required further review.
Of these, more than half were ultimately determined to be likely cases of food-poisoning linked to the restaurant.
A Boston Children’s Hospital study also noted that Yelp “reviews describing food poisoning tracked closely with food-borne illness data maintained by the Centers for Disease Control and Prevention.”
But as seemingly accurate as these negative reviews and experiences may be in tracking potentially deadly diseases, it’s not always a straightforward process. As anyone who’s frequented Yelp may tell you, some reviews are written more to pick a bone than to actually relate an experience. And even more problematic is Yelp’s system of hiding some reviews while promoting others. In the case of the Mariscos San Juan restaurant, a number of reviews that spoke to food poisoning were actually blocked from easy view in Yelp’s “not currently recommended” tab.
Yelp notes in a blog post that it attempts not to “highlight reviews written by users we don’t know much about, or reviews that may be biased because they were solicited from family, friends, or favored customers.”
So by all means, take your Yelp reviews with a grain of salt. But if people are talking bodily fluids after a restaurant visit, you may want to consider steering clear for awhile.
