Dining out with Bayes Theorem (Updated)

Imagine you’re looking for a place to eat. Say for example you’re in the mood for Mexican food. So, you go to Yelp and type “Mexican” into the search bar and up come a variety of results.

After scrolling through the list, you pick one that seems like it could be good. It’s nearby, not too expensive, and most importantly it gets a positive rating on the basis of a fairly decent number of reviews. Let’s say it gets 4 stars based on 17 reviews.

Here’s the question I pose to you – just how much can you trust this 4 star rating? How do we know that this rating is a fairly accurate reflection of the quality of the food and overall dining experience at this restaurant? And how do we know that this rating is not merely due to some other extraneous circumstance? (more…)

correlation between number of reviews and discrepancy

What’s the best place in Charlotte to get Thai Food? A trial run of our statistical model (Part 1).

In this post, we’re taking the Charlottology Statistical Model of Restaurant Reviews out for a test spin by applying it to some real restaurant ratings from Yelp. I described the workings of the model in my last post, so I won’t go into as much detail on methodology in this post. If you have any specific questions regarding our methods, feel free to check out that earlier post.

We’re focusing here on the question of, “where is the best place in Charlotte to get Thai food? (more…)

Figure 3B

The Charlottology Statistical Model of Restaurant Reviews

In my last post, I outlined what I see as being one of the more frustrating aspects of trying to select a restaurant based on search results from If you haven’t read that post, my argument was essentially that Yelp seems not to give enough weight to the number of reviews upon which average restaurant ratings are based. Because of this, Yelp will for instance rank restaurants with 4.5 stars based on 10 reviews as being superior to restaurants with 4 stars based on 400 reviews. This is a problem because the difference in average ratings between these two restaurants may be entirely a statistical artifact. In reality, there may be no difference in quality between these two restaurants, or the restaurant with the higher number of reviews (and ranked lower by Yelp) may actually be far superior. (more…)