When It Comes to Movie Rating Websites, There is Strength in Numbers.

If you can only use one website to help you select movies that you will “really like”, which should you choose?

If you can only use one website to help you select movies that you will “really like”, which should you choose? That’s a tougher question than you might think. Because I have used all five of the websites recommended here to select movies to watch, my data has been heavily influenced by their synergy. I have no data to suggest how effective using only one site would be. Here’s what I do have:

Probability I Will “Really Like”
Recommendation Standard When Recommended in Combination with Other Sites When Recommended by This Site Only
MovieLens > 3.73 70.2% 2.8%
Netflix > 3.8 69.9% 8.4%
Criticker > 76 66.4% 10.1%
IMDB > 7.4 64.1% 0.3%
Rotten Tomatoes Certified Fresh 62.7% 4.3%

When MovieLens recommends a movie, in synergy with other websites, it produces the highest probability. When Criticker recommends a movie but the other four sites don’t recommend the movie, then Criticker has the highest probability. Netflix is second in both groups. Which one is the best is unclear. What is clear is that the three sites that recommend movies based on your personal taste in movies, MovieLens, Netflix, & Criticker, outperform the two sites that are based on third party feedback, Rotten Tomatoes and IMDB. When Netflix, MovieLens, & Criticker recommend the same movie there is an 89.9% chance I’ll “really like” it. When both IMDB & Rotten Tomatoes recommend the same movie the probability is 75.8% I’ll “really like” it.

What also is clear is that if four websites are recommending that you don’t watch a movie and one is recommending that you do, the probability is that you won’t “really like” the movie no matter how good that one website is overall. The progression of probabilities in the example below gives some perspective of how combining websites works:

Websites Recommending a Movie Probability I Will “Really Like”
None 3.9%
Netflix Only 8.4%
Netflix & MovieLens Only 31.9%
Netflix, MovieLens, & Criticker Only 50.9%
Netflix, MovieLens, Criticker & IMDB Only 71.1%
All Five 96.6%

Stated Simply, your odds increase with each website that recommends a particular movie. If, for example, you were to only use Netflix for your movie recommendations, the probability of “really liking” a movie might be 69.9% but, in reality, it could be any one of the probabilities in the table above with the exception of the 3.9% for no recommendations. You wouldn’t know if other websites had recommended the movie.

So, if I had to choose one website, I’d choose Netflix-DVD if I were one of their 5,000,000 DVD subscribers. If I’m not already a subscriber I’d go with MovieLens. It would be a reluctant recommendation, though, because the strength in numbers provided by using multiple websites is just so compelling.


You’ll notice in the Top Ten Movies Available to Watch This Week that there are a number of movies on the list that are available on Starz. I’m taking advantage of the Comcast Watchathon Week which provides for free Starz, HBO, & Cinemax. Some of my highly rated movies which would ordinarily be unavailable are available for the short duration of this promotion. Bonus movies. Wahoo!!



Author: Mad Movie Man

I love good movies. In my prior life I worked with predictive models. I've combined my love of movies with my prior experience to create a simple Bayesian probability model to help select movies that you will probably "really like".

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