Content-Type: text/shitpost

Subject: How I rate restaurants
Path: you​!your-host​!warthog​!gormenghast​!extro​!forbin​!berserker​!plovergw​!plover​!shitpost​!mjd
Date: 2017-11-16T12:33:13
Message-ID: <>
Content-Type: text/shitpost

Yelp asks me to give restaurants a rating of between one and five stars. This suits me. People sometimes ask me to rate things on a scale of one to ten, and I never feel like my discrimination is delicate enough to warrant so many different grades. What's the difference between a 6 and a 7? I'm not sure.

I have a standard system to convert my overall impression to stars. The most common rating is three stars:

☆☆★★★ “Good”

I would not make a special trip to come here, but I would willingly eat here again. If a three-star restaurant is convenient, I would probably eat here regularly.

“Hey, want to go out to eat?”
“Did you have somewhere in mind?”
“Well, we could go to Jimmy's.”
“Sure, Jimmy's is always good!”

☆☆☆★★ “OK, I guess”

I would eat here again if there was no immediately better choice, but I would prefer to take my chances with a new. untried place.

“Geez, we're going to be out in the Sandy Bottom District this evening. There's nothing to eat over there.”
“We could go to Jimmy's.”
“Ehhh, yeah, I guess that's what we'll have to do.”

☆☆☆☆★ “Bad”

I would prefer to go hungry than to eat here again.

“Geez, we're going to be out in the Sandy Bottom District this evening. There's nothing to eat over there. Except… Jimmy's, I guess.”
“Ugh. Better take along some sandwiches.”

Yelp doesn't allow fewer than one star, which is fine with me.

Going in the other direction, we have:

☆★★★★ “Excellent”

I look forward to returning here. I get excited at the thought of coming back, and would make a special trip.

“Hey, want to go out to eat?”
“Where did you have in mind?”
“We could go to Jimmy's.”
“Sure, I love Jimmy's! It's kinda far away, but it's worth the trip.”

★★★★★ “Outstanding”

One of the best places I've ever been. Worth traveling a long way. I only give out a couple of these a year.

“You're going to be in Salt Lake City? Oh, man, you have to try Jimmy's. It's a 45-minute drive, but you'll be glad you went.”

My impression of Yelp ratings is that this is atypical and that ratings are heavily weighted toward four and five stars, and that by giving three-star ratings to restaurants I like, I am doing them a disservice. That is unfortunate for everyone. Here are the rating distributions of a user A, on the left, and myself, on the right:

User A User B

Some upward skew is to be expected. There are plenty of mediocre restaurants that I don't bother to review, but when the food is good I get excited to tell people about it.

But clearly, the two of us mean something very different by five stars. When I give a restaurant five stars, you know it means I like it better than 82% of the other restaurants I've reviewed. When use A gives five stars, all you know is that it's better than the worst 30%.

I've often wondered how hard it would be to weight different users’ ratings, so when user A gives out five stars two-thirds of the time, their stars are not worth as much as those of user B who awards five stars only one time in six. And conversely, user A's rating of one star seems to be more significant than mine, because a one-star restaurant is in the bottom 3% for user A, but only the bottom 10% for me.