While working on our main business SaidThat (saidthat.com) our team noticed that IMDb's star ratings consistently seemed to disagree with other major review sites (RottenTomatoes, MetaCritic, TMDb, etc). We found that IMDb only tended to match those other scores when you took the simple average of the user text review ratings as opposed to the normal star rating.
To show case this we built a fun little demo site that will quickly calculate the simple average for you and then show you how "inflated" the quoted IMDb star rating is. You can do this for any movie or tv show!
We fully recognize there are numerous legit reasons for these discrepancies (we wrote a whole page about it on the website honestimdb.com/about), but we will leave forming an opinion up to you. It's just interesting to note the difference seems more extreme and frequent on Amazon (who owns IMDb) originals...
