Sunday, September 20, 2015

Be Suspicious of NYC Restaurant Health Ratings

Whether you pay serious attention to them, or don't, each restaurant in New York City has a grade posted outside indicating its health grade. Among the 24639 restaurants in the recently published NYC Restaurant Inspection Result Dataset, nearly 80% of the restaurants have been awarded an "A" safety rating, 15% have been awarded an "B" and 5% have gotten "C" or worse.

However, should New Yorkers really trust these health ratings? Ben Wellington of I Quant NY made an compelling case showing that health inspection scores, which help classify restaurants into grades (score of 0-13 is an "A", 14-27 is a "B", 28+ is a "C"), suffer from the "bumping up" syndrome, meaning that restaurants on the cusp of a higher grade tend to be bumped up to the higher grade.
Furthermore, health inspections are made on a random basis annually, meaning that health grades only represent safety conditions in the past year.

Sadly, an examination of the history of health inspection grades of New York restaurants suggest an inconvenient truth - many restaurants considered "safe" today have not always been "safe" in the past. This may mean either that restaurants improve their sanitary conditions significantly after a health inspection, or that inspectors tend to "bump up" restaurant grades from one year to the next.

As seen in the graph above, a majority of restaurants that were rated "B" and "C" in their infancy end up becoming grade "A" restaurants - at an astonishing 72% and 65% respectively. From the opposite point of view, 25% and 15% of restaurants which are now grade "A" restaurants actually started off at a grade "B" and "C" sanitary level. Given that most restaurants in NYC do not have a very long life span (80% of NYC restaurants close after 5 years) and that this grading system was only formally established 5 years ago, having so many restaurant grades increase in such a short time leads us to question whether the letters at the front of every NYC eatery are truly reliable.