IMDB Top 100K Movies – Analysis in Depth, Part 2

That or it is becoming increasingly harder to entertain people with new ideas as they watch more and more movies. People could be getting desensitized to entertainment.

Is there any way to extract movie ratings vs time from your data-set? I've subjectively noticed a few patterns in movie ratings, and would love to see quantitative confirmation.

1. Rating quality tends to spike at or shortly after a film's release, but then drops off gradually as the glow of the PR campaign wears off, or perhaps because people who go to see movies in their opening week are more predisposed to like them (e.g. fanboys, etc.). I usually expect a film that has just been released to be similar in quality to a film that's been on home video for a while with a rating half a point or more lower. (I am ashamed to admit that I watch enough movies that I can usually peg it's IMDB rating to within a quarter of a point independently from how much I personally enjoyed the film. )

2. Rating quality for older films tends to be held back by poor quality home video releases and often improves significantly, but gradually, after quality transfers are released. e.g. I distinctly remember seeing Zulu several years ago and thinking, "Gee, that film was way better than the IMDb rating!". Back then, it was in the high 6 range. Now it's up to 7.8!

I suspect IMDB does not keep track of times associated with votes, or at least does not provide that data publicly, so the best you could do would be to crawl IMDb periodically. It shouldn't take more than a year's worth of data to see if point #1 holds up. #2 is a lot more difficult because the effect is more gradual, and you'd need to start bringing in other data sources, like audio/video quality ratings from home video review sites that do tend to be somewhat unreliable. I find #2 to be a question of interest though. If you found any other form of correlations with titles whose ratings improve substantially after quality home video releases, you would have potentially found a way to identify under-appreciated films. If you pulled that off, in addition to discovering some good flicks to watch, companies like Kino and Criterion would probably start knocking at your door!

eg Batman: The Dark Knight Rises gets 8.6 http://www.imdb.com/title/tt1345836/

1) Don't forget that the raters are self selecting. For very recent movies, the ratings will only be from people who were attracted by hype, and were excited enough to immediately rate a film.

2) All of those ratings will eventually drop as people outside of the target audience(outside of the natural consumers of initial hype) rate the film, reverting the rating to the mean.

3) Most people that are aware of a particular older film are people who remember it because it was/is a favorite, or people who encountered it recently and found it interesting enough to research it on imdb, both probably tending to skew positive.

If you were able to collect the changes in ratings over time, I'd bet that dip of low ratings would always be around the same distance from the present.

I might be off on this, though, because there will always be a qualitative separation between movies that were ratable at the time of release, and movies released pre-imdb.

I hope you'll get a chance to check out writers after actors. It'd be a really interesting test of Schrieber theory, which argues that the writer is a better predictor of a film's quality than the director.

http://en.wikipedia.org/wiki/Schreiber_theory

(I had a similar comment last time, sorry for hounding the same issue, just not sure if you saw it.)

From my own (anecdotal) observation, there's a class of films where the 'Females 45+' rating is a big outlier in the voting, with a large proportion of '1' votes. it's as if there's a gang of a few hundred users consistently downvoting films who are classed by IMDB as being part of that demographic - I don't know if it's a default setting that some bots or trolls have used or if there really are a bunch of cinephobic old women out there just watching and hating on films, but it did spark my curiosity as to what the pattern was. It doesn't happen in every film, and it's rare that you see any other demographic sticking out like this.

The best examples are critically acclaimed films with low voter counts. More popular, or less well-received films tend to have a lot of negative noise to begin with, so the effect is less noticeable, if it's there at all.

Here's some examples:

Army of Shadows : http://www.imdb.com/title/tt0064040/ratings?ref_=tt_ov_rt

Spartacus : http://www.imdb.com/title/tt0054331/ratings?ref_=tt_ov_rt

Ikiru : http://www.imdb.com/title/tt0044741/ratings?ref_=tt_ov_rt

Passion of Joan of Arc : http://www.imdb.com/title/tt0019254/ratings?ref_=tt_ov_rt

Breathless : http://www.imdb.com/title/tt0053472/ratings?ref_=tt_ov_rt

Z : http://www.imdb.com/title/tt0065234/?ref_=fn_al_tt_2

Barry Lyndon : http://www.imdb.com/title/tt0072684/ratings?ref_=tt_ov_rt

I don't believe it is, and I think the further back you go, the more likely it is that only well-regarded films are in the database.