Many sites on the internet rate or rank the best and/or worst episodes of Buffy the Vampire Slayer. Very few are as thorough as this site, so their rankings may not be as definitive. However, they do an adequate job. This site does more, however. It examines characteristics associated with the best and weakest episodes. This site looks at four factors that may affect the quality of an episode: when the episode aired (what season and when in the season), how many lines various characters had in the episode, who wrote the episode, and who directed the episode. The links below lead to pages that examine the relationship between each of these factors and the quality of an episode and ranks the seasons, characters, writers, and directors by how much they may contribute to the quality of an episode.
When an Episode Aired—Looks at how episode quality varies from season to season and also notes the effect of airing first, last, or second to last in a season and of being part of a two-part episode.
Characters—Looks at how the number of lines 27 major characters plus two groups of characters have in an episode is related to the quality of that episode.
Writers—Looks at the relative quality of episodes depending on who wrote them.
Directors—Looks at the relative quality of episodes depending on who directed them.
When the four factors above are combined, they explain about three quarters of the quality of the episodes. The Predicted Quality page shows how the episodes would be ranked if the four factors described above were the only causes of episode quality. The four factors almost completely explain the quality of some episodes. For other episodes, some unmeasured factor either boosts their quality or detracts from their quality. The Mispredicted Quality page presents a list of the episodes that are either much better than or much worse than we would predict, given what we know about those episodes.