Do user ratings of products — games, films, books, restaurants, etc. — tend to follow any particular distributions? If so, what form do they commonly take? Are there public data sources that show these distributions (e.g. for Amazon books, Netflix movies, etc.)?
- Anybody can ask a question
- Anybody can answer
- The best answers are voted up and rise to the top
Here's a post from the YouTube blog that, anecdotally, I think is fairly representative of star ratings systems online generally.
As you can see, it's a J-curve.
Here are some further examples from different sectors, with the graphs reproduced here:
The biggest relevant dataset I'm aware of was the one Netflix released for the Netflix Prize competition – however it has since been removed due to a privacy lawsuit. You may however be able to find copies of it online.