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Do TV Series Get Better Or Worse Over Time? Let's Crunch Some Numbers


In May of this year, I spent a long, slow day at work penning an article comparing the ratings a network television series receives on IMDb with its fate in the renewals and cancellations. The conclusion was reasonably straightforward, but the numbers were fascinating to analyse, and given the level of discussion generated, I felt compelled to take the concept further.This time, I sought to leave Nielsen out of the picture entirely, and instead ask the question of whether a television series gets better during a season, and during its lifetime. I wanted to know whether those episodes in a series that blew my mind were received in a similar fashion by most other fans, and vice versa for those episodes which fell a bit flat.IMDb visitors, in addition to giving a series an overall star rating out of 10, can also rate individual episodes out of 10. It's worth noting that the difference in the quantity of votes between the two can be rather large, and from my analysis, season and series premieres, tend to have higher vote counts than other episodes. Also, bear in mind that individual episode ratings have no bearing on a series' overall rating.A term I've seen referenced on the internet on this subject is survivor bias, not to be mistaken for survivorship bias, which has its roots in economics. In television terms, it proposes that the critics view and rank the first few episodes, but if they call it quits on a series, only those that like the series are left to rank its episodes, which can in theory skew the results. From what I've seen, survivor bias presents itself the strongest right at the beginning of a series but doesn't flow on to future seasons. Bringing dreaded Nielsen back into the fold for a moment, this makes sense because series premieres often rake in big audiences, but said audiences drop and flatten out fairly quickly.To analyse the data, I'm using a site called, a beautifully simple site that allows you to simply type in the name of a series and see its data in graph format. If I don’t mention your favorite series in this article, you can go to the site and check your own shows out yourself. The graphs on the site are also a lot larger, and are interactive.To kill two birds with one stone, let's look at some long running medical dramas for starters. FOX's House MD was on our screens for eight terrific seasons, and sits among the best rated television series on IMDb - an 8.9 rating from 229,445 ratings to be precise. Its lowest rated episode (7.7) came in its final season, and its two highest rated episodes (9.8) came in its fourth season. Two of its 8 seasons trended down, while 6 trended up, with the steepest slope seen in season 5. Surprisingly, House MD trended down over its 8 seasons, as can be seen by the white line in the graph below:house.jpegEntering double figures this year is ABC's longest running current scripted series, Grey's Anatomy. It's received 120,109 overall ratings, which averages 7.7. Two episodes in season 6 touched 9.3, with the lowest rated episode airing in season 3, garnering a 7.3 rating. Seasons 6 through 8 have trended flat, but its ratings surged last season. Like House MD, it trends down marginally across its lifetime, as seen in the white trendline in the graph below:greys%2Banatomy.jpegOff the top of my head, ER and Scrubs are two other long running medical dramas. ER trended up overall, and surged in its last season, while Scrubs went the other way. Crime dramas are another popular genre, and one that has a good selection of shows this upcoming season. There's also a few stalwarts around. CBS's NCIS enters its twelfth season this month, and its data makes for interesting reading too. The series has an 8.1 overall rating from 63,279 viewers - a surprisingly small sample size given its longevity. Like House MD, NCIS underwent a cast shakeup in its third season which must have had an impact on its popularity as the season trended down, but the absence of Cote de Pablo last season saw season 11 trend slightly upward, albeit to a lower extent than previous seasons. Overall, the series trends up. Its graph is below:ncis.jpegFellow CBS series Criminal Minds chalks up a double figure season count this month also. Its ninth season saw a much steeper incline in individual episode ratings than any other time in its history. Its one of the only series I've looked at in which the first season trends down, albeit marginally. Criminal Minds has two dozen episodes with an individual ranking higher than 8.5, but none beyond 8.9. Its lowest rated episode came in at 7.4, and aired in its freshman season. However, despite the ninth season rally, the series trends marginally down, as can be seen below:criminal%2Bminds.jpegABC's Castle is also worth a look. Compared to most other series, Castle's trendlines are very consistent, though the episode ratings vary wildly. Three of its season finales sit at a 9.0 rating, and all but 2 of its premiere and finale episodes rank above the series trendline. I can't help but take a stab at the most recent season finale, which sits more than half a point below the trendline (I wonder why). An 8.3 overall rating from 88,826 votes reflects its popularity, but interestingly its first season, which some argue is its best, is its lowest rated. Its graph is below:castle.jpegFOX's Bones is a mixed bag if there ever was such a thing. It's another series entering double figures this month. A total of 83,541 votes have been cast, giving Bones an 8.1 overall rating. Only two episodes from its more than 200 have received a 9.0 rating (there are none rated higher) one being the most recent season finale. The series' lowest rated episode came in season 8 and garnered a 6.3 rating. I'm sure a Bones fan will let me know why that episode wasn't well received in the comments. Aside from that, the overall series trendline heads downward, while each season bar a couple tends to head upward. Its graph is below:bones.jpegEnough of the veterans, let's have a look at some newer series, yet well established series from the last few years. Person of Interest is a great place to start, especially given that it's my favourite television series. It's received an 8.4 overall rating from 78,894 votes, and you know a television series is a goodie when you take into account that not one episode has an individual rating less than 8.1, with the three highest episodes, all from season 3 and including the season 3 finale, have a 9.8 average rating from well over a thousand votes each, one of the best sample sizes per episode you'll see. It's not surprising that each season and the series overall all trend upwards, with nearly two thirds of episodes in season 3 receiving ratings higher than 9.0, compared to 5 in its freshman run.person%2Bof%2Binterest.jpegABC's Once Upon A Time is consistently one of SpoilerTV's most popular series. IMDb users also rate it, with 117,907 ratings equating to an 8.1 average. Once Upon A Time has been on the air for three seasons, and its last season saw a strong increase in its episode ratings, with the season finale garnering the highest episode rating yet, a 9.5 averaged from 855 votes. All of its premieres and finales sit higher than their respective season trendlines too. Its graph is below:once%2Bupon%2Ba%2Btime.jpegAnother ABC series scoring well on IMDb is Scandal. After three seasons of varying lengths, Scandal enjoys a 8.0 rating, though the sample size is rather small at 30,669, which shows in this case that social media popularity doesn't necessarily mean IMDb popularity. Despite its current fame, the series premier is the lowest rated individual episode by a large margin, and only one episode has garnered a rating higher than 9.0, though the third season finale equals that rating. Despite the low rated series premiere, the trendline for season 1 is steep, and the two most recent seasons share a similar upward gradient. See the graph below:scandal.jpegMay wasn’t particularly good to me in terms of freshman series being picked up for a second season, but let's look at a few of the bigger names anyway. James Spader's The Blacklist led the way by more than a few country miles. The IMDb data corroborates this, with a steady first season trendline beginning at 8.0 and ending past 8.5. The series has an overall 8.2 rating courtesy of 43,601 votes, and each episode receives a good sample size too. While no episode has fallen below a 7.8 rating, only a third of its episodes actually sit above the trendline, as seen in the graph below:the%2Bblacklist.jpegThe 100 was CW's big hit with its 13 episode first run beginning in late March. Like Scandal, its series premiere was the least popular among IMDb voters, garnering a 7.5 rating, but its freshman season finale sat at the other end, with a 9.0 rating. The survivor bias theory may hold some weight here, with the premiere receiving around 50% more votes than most of the other episodes. The season went on to earn an overall average of 7.5 based on 18,849 ratings. Its graph is below:the%2B100.jpegFOX's Sleepy Hollow made for interesting reading. It garnered a 7.8 overall rating courtesy of 29,331 votes, but only one episode was given a rating equalequalling that, with none rated lower. The 100 also shares this trait. The highest rated episode in its 13 episode run was the season finale which received a 9.1 rating, and was the only episode to break the 9.0. As you'd expect, its overall trend was upwards.sleepy%2Bhollow.jpegThe last freshman series I'll take a look at is ABC's Agents of SHIELD. Much like Sleepy Hollow it started rather slow with no episodes in the first half of the season threatening the 8.5 benchmark. Again like Sleepy Hollow, only one episode from the season garnered a rating lower than its overall 7.4 rating from 62,319 votes. The top half of the season saw no episodes rated lower than 8.1, with the most well received episode garnering a 9.4 rating, compared to the season finale's 9.2 rating.agents%2Bof%2Bshiield.jpegIt's also worth taking a look at some cable series. The most popular cable series of the last few years is without a doubt HBO's Game of Thrones. Game of Thrones sits among the highest rated television series on IMDb, with a 9.5 rating sourced from 636,266 ratings. Each episode receives thousands of ratings, making for a great sample size. All four seasons feature a steep upward trendline, and it should come as no surprise that the overall series trendline heads in the same direction. game%2Bof%2Bthrones.jpegShowtime's Homeland was snubbed at this year's Emmy Awards, and its trendline for season 3 probably explains why. Its two lowest rated episodes aired last season, though it also equalled its highest rated episode last season, a 9.2. The series has an overall 8.5 rating garnered from 152,985 ratings, and the series trendline runs as near as makes no difference to horizontal, as you can see below:homeland.jpegAs online companies take up the challenge of producing their own series, there aren't many ways to determine the success of a series among its fans because television ratings become irrelevant. Netflix is one such example, with flagship series House of Cards and Orange Is The New Black both having screened their sophomore seasons. The former has a 9.1 overall rating from 142,859 votes, with the sublime season 2 premiere and finale both taking the title as the series' top rated episodes to date, sharing a 9.6 rating. House of Cards has been trending upward steadily, with the trendline for the second season beginning at a higher point than the Is The New Black is enjoying plenty of acclaim in the wake of its second season. The series premiere has the series' lowest episode rating at 7.9, while the season 2 finale garnered a 9.6 rating, surprisingly high considering no other episode has a rating beyond the 9.0 benchmark. Overall the series has an 8.5 rating from 91,197, does Breaking Bad really deserve its accolades? IMDb users think so, with an enormous number of votes for each episode. It ended its 5 seasons with a 9.6 overall rating from 545,616 votes, and after a flat first season, it there was only one direction the trendlines could head.breaking%2Bbad.jpegIf you've made it to this point in the article, you deserve a pat on the back because you’ve read just over 2100 words, so now's a good time to bring things to a close. IMDb isn't a perfect source for determining the true quality of a series, but it's probably the best you'll find, it's easy to analyze, and it has a solid sample size. Of course, a series' overall rating and its individual episode ratings will always be subject to die-hard fans rating each episode a full 10, but the same can be said for trolls who give everything the lowest possible rating. From the series I've examined and featured in this article, the majority of seasons trend upwards from their season premieres, but it's not uncommon to find a series that trends down overall. Survivor bias may or may not be present in a lot of the data, and each series will be subject to countless other factors which determine the ratings it receives. It goes without saying that there's countless other series that I haven’t mentioned in this article, so please feel free to look your favorites up on and post your findings in the comments below. Thank you very much for reading, and please share this article to your fellow fans using the social media buttons on the left hand side of your screen.Jimmy.

About the Author - Jimmy Ryan

Jimmy Ryan lives in New Zealand. He is an avid follower of drama television and has a keen interest for television ratings and statistics. Some of his favorite shows right now are Person of Interest, Scandal, House of Cards, Orphan Black, The Blacklist, The 100, and Castle. You can visit his television ratings website, or follow him on Twitter,@SeriesMonitor.

Stashed in: Game of Thrones!, Are You Not Entertained?, Breaking Bad, LOST!, Dexter, Telly

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Dexter is not in your charts! It got worse over time, as did LOST. 

Breaking Bad got better over time, as has Game of Thrones so far.

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