How to Read Movie Ratings: IMDB Analysis

(3 minute read)

What's a good movie rating? Is it an 8 out of 10? Should I only watch movies that received at least 75% on Rotten Tomatoes?


I've explained how Rotten Tomatoes judges movies in a post here, but meanwhile IMDB (the Internet Movie Database), which originated in 1990, asserts to be "the world's most popular and authoritative source for information on movies, TV shows, and celebrities". Cocky? Nope, IMDB is very well-regarded in the film industry and usually my go-to source when checking a movie's performance.

Submitted ratings are also highest in volume on IMDB than on any other review website. Here are two examples below:

Spider-Man far from Home (2019) - because I just saw it
- 55k reviews on IMDB
- 30k reviews on Rotten Tomatoes
- 380 reviews on Metacritic

The Godfather (1972)
- 1.4M reviews on IMDB
- 1.2M reviews on Facebook - probably not the best source for critical reviews
- 732k reviews on Rotten Tomatoes
- 2.5k reviews on Metacritic

Therefore, if you want to check if a movie is worth your time, you'd have better luck checking IMDB first, which has more votes a.k.a a larger sample size thus more statistical power. 


I took a little shy of 1,000,000 IMDB ratings (949,490) and plotted what's called a histogram, a chart of the counts of all the ratings. FYI they publish their raw data here. Here's what I found...

As you can tell, the most popular review falls around the 6 to 7.5/10 region, but the real numbers to look at are the mean - 6.9 out of 10 - and median - 7.1 out of 10.

Some posts by people on Stack Overflow and Quora will profess that the average is 6.5/10, but with the latest data here, some simple number crunching recommends that anything with at least a 7 out of 10 on IMDB ratings is considered "good" or "average".

Therefore, the next time you want to check how a movie scored among critics, type the title into Google and check the IMDB rating in Google's Knowledge Chart, the box on the right-hand side. Hope this helps!

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