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[Comments] (6) Worst Episode Ever: Time for some more IMDB fun. Last time I looked at whole years of television. This time, I'll graph the ratings for individual episodes of TV shows. Can we watch shows get better or worse over time?

We sort of can. The problem is that only a true fan bothers to go to IMDB and rate individual episodes of a TV show. So you can't really trust the episode ratings--they're too high. But we can visualize trends in show quality, as percieved by the fans.

For these visualizations you want long-running series with lots of die-hard fans. So let's start with Star Trek:

(Note the very last data point in that one. That's the series finale, which everyone hates.)

There's a lot of scatter, but you can generally see the common Star Trek pattern of the show getting better as the ensemble cast comes together. Except for the original series, which ended with a lousy season. Now let's look at another nerd favorite, "Buffy the Vampire Slayer":

Beth requested that one. I've seen exactly one episode of Buffy so I wasn't expecting anything in particular. It looks like a show that's consistently good, but wildly inconsistent within the bounds of "consistently good". It doesn't really get better over time. Maybe the Voyager and DS9 graphs look the same to someone who's not a Trek fan.

But compare "Mystery Science Theater 3000", which gets drastically better over time. When I was younger I would have disputed this finding, but now I basically agree with this graph:

I did a lot more graphs, but I'll just show two more. Here's the graph for "The Simpsons", a very long-running show with a very fickle fan base (see title of this post):

Wow! I love this graph! I don't know enough about the history of the show to name the historical trends, but I'm pretty sure a Simpsons fan will be see a big part of their life history reflected in this graph.

I wanted to see if this sort of coherent shape was just an artifact of the fact that "The Simpsons" has been on the air for over 20 years, so I graphed another long-running show notorious for huge variation in quality, "Saturday Night Live":

You can definitely see where things went wrong, but even within a season there's huge variation in quality. The Simpsons is created by the same people every week, where SNL has two wild cards every week: its guest host and musical guest. And since it's sketch-based, three good or three awful minutes can make or break the entire episode.

Next up, the third and possibly final part of this analysis, in which I'll pit fans of a show against the general public.

PS: For the record, according to IMDB data, the actual worst episode ever of "The Simpsons" was #9.11, "All Singing, All Dancing".

Update: People in comments had questions I can't answer because I only know how to do very basic statistics, but they also had questions about how many people rated the episodes, which I can answer. This table shows how many people have rated each series as a whole, as well as the median and mean numbers of ratings for every episode that has any ratings. I also included how many people rated the first episode, how many rated an episode in the middle, and how many rated the last/most recent episode.

Series Series ratings Show ratings (median) (mean) (std)First showMiddleMost recent
"Buffy the Vampire Slayer" (1997) 34564 498 553.41 224.888625111091
"Enterprise" (2001) 8843 140 189.27 242.282397130152
"Mystery Science Theater 3000" (1988) 6650 57 65.54 47.412178131
"Saturday Night Live" (1975) 10151 15 19.86 15.651121160
"Star Trek" (1966) 12695 419 480.95 222.836683891923
"Star Trek: Deep Space Nine" (1993) 9779 172 188.32 107.371501151290
"Star Trek: The Next Generation" (1987) 16974 329 375.62 354.4921893184580
"Star Trek: Voyager" (1995) 11245 153 169.08 110.961558177348
"The Simpsons" (1989) 15578 319 355.07 173.09221430996

So SNL actually has very few ratings per episode, while The Simpsons is on par with ST:TNG. It's common for the first episode and the finale to have many more ratings than others. And here's a graph of the number of people who have rated "The Simpsons" over time:


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