There are a number of series that have even more pronounced and steady declines (Jaws, Planet of the Apes). Other series have a more chaotic progression. The even number rule for the Star Trek series is reasonably pronounced, except for part 10 (the reboot is not included, though I imagine it would be higher than the last two). The Indiana Jones series has a similar progression, except it's the odd number movies that are the best. I'm a little surprised at how low Die Hard 2 is in the series (it's at least as good as the other sequels). It's also a bit strange to see the latest Rocky and Rambo installments being so high. Perhaps that's because the source appears to be IMDB, and ratings there tend to favor newer movies for a while (after time, these movies tend to level out to more reasonable ratings). Interestingly, the Lord of the Rings trilogy features the most consistent ratings. There are a lot of series that have solid first and second installments, but the third movie is almost always a big decline.
Of course, the listed series are not comprehensive, so I took a few stabs at the missing series. Here, for instance, is the Friday the 13th series:
I have to admit that I'm a little surprised that parts IV and VI, which seem to be the fan favorites, are as low as they are. Of course, they're pretty high compared to most of the films around them, but still. I expected them to be a bit higher. Also, part 2 and the recent reboot seem extremely overrated. The reboot will most likely come down as time goes on (again, I think newer movies benefit from IMDB's system), but the love for part 2 confuses me. I suppose part 2 does have probably the best final girl in the series (and maybe of all time), but the story is crap and the ending is nigh incomprehensible. And Jason isn't even close to becoming an iconic character in that movie.
More series in the extended entry, including the likes of Halloween, Evil Dead, Dirty Harry, Bourne and more! And so we might as well continue the 80s slasher series, here's Halloween:
Mostly unsurprising. The one major outlier is part 3, which makes sense because that was the one that didn't feature Michael Myers.
This series is surprisingly stable. However, I think that the second one is a bit underrated, while the fourth through sixth might be a bit inflated. Also notable is the seventh installment, which rockets back up near the original. I'm not a big fan of New Nightmare, but it's definitely more interesting than most of the films in the series and the return of Wes Craven translates pretty well to higher ratings...
Another extremely stable series, though the second installment is clearly the best.
A pretty clear and definite decline in the series. Notable in that it's one series that hasn't really had a reboot (not that I want one - totally unnecessary).
Interestingly, this is the only series in this post to feature a third installment that has better ratings than it's predecessors. I have to admit that I'm a bit surprised by that. I really like Bourne Ultimatum but I wouldn't put it as that much better than the previous two installments.
Well, that's all for now. In other news, Flyers lost the Stanley Cup tonight. I'm glad they put up a good fight, but what a terrible goal to lose on... In any case, congrats to Blackhawks fans.