Restaurant reviews, some of them — especially the reviews written by non-professionals — have taken on new importance. They can be a means of identifying illnesses that otherwise go unreported to health officials. Mary McKenna (who is sometimes known professionally as “Scary Disease Girl”), writing on The Plate blog, explains:
Yelp Helps NYC Health Department Track Foodborne Illnesses
Today, in its weekly news bulletin, the Centers for Disease Control and Prevention reports on an innovative project that the New York City health department tried out for nine months in collaboration with Yelp. The team examined more than 294,000 reviews posted to the site between July 2012 and March 2013; found that 468 of them reported people getting sick after a meal; and discovered, within those 468, three foodborne illness outbreaks that authorities not known about. Only 3 percent of the illnesses listed on Yelp had ever been reported, by the sick people or their doctors, to the health department.
This is a big deal, several different ways. First, because this data—the reviews—are available for anyone to read, whereas foodborne illness information is notoriously difficult for public-health authorities to get hold of. (Think about it. The last time a presumably food-related illness took you down, did you call your doctor, or tough it out yourself?): The CDC itself acknowledges that its national figure of 48 million food-related illnesses each year is only an estimate, since as few as 2 percent of them get medical attention. And, second, because it offers a tiny step into a problem that public-health types are obsessed with: How to make practical use of the masses of data that swirls around us every day, and that we all contribute to, by texting, Tweeting, posting to blogs, updating Facebook, and so on.…
(The full cite for the New York City department’s paper is: Harrison C, Jorder M, Stern H et al. “Using Online Reviews by Restaurant Patrons to Identify Unreported Cases of Foodborne Illness—New York City, 2012-2013.” It is being published in the CDC’s Morbidity and Mortality Weekly Report.)
One must, of course, always be careful in interpreting data, especially to compensate for known types of error. Yelp, the data source used in this medical investigation is, like most sources of most data, not perfect.