[bugra]

It is true that as runtime increases, the number of movies decreases. However, if you look at the mainstream runtimes(>80 and <100), generally they get quite a variety of ratings for a given runtime if not uniform. On the other hand, the movies that have higher runtimes generally get higher number of votes.

You could also observe the same behavior from rating vs #votes graph; as # votes increases, the number of movies decreases. However, rating and # votes correlate quite strongly.

[_mulder_]

I wonder why long movies are consistently rated higher? My guess would be for two reasons. The first being audience selection. Long films are (IMO) more likely to attract, and retain for the entire length, an audience with a prior interest in the film, and therefore more likely to be an audience who know beforehand if the movie is generally good or not.

Secondly, psychology will come into play. The more time an audience invests in a film, the more likely they are to seek a positive reward for their time so they don't feel like they have got a bad deal[1]. Thus, they're more likely to rate the film higher than it perhaps otherwise would be. I also believe this holds true for 'art house' films that are difficult to follow and perhaps less enjoyable than a more mainstream film. Audiences will rate them higher to reassure themselves that they haven't just wasted 2 hours watching something boring that they don't understand.

Some links for further reading: http://en.wikipedia.org/wiki/Irrational_escalation http://en.wikipedia.org/wiki/Post-purchase_rationalization