TV Series that passed their peak

TV Series	Duration	First Season Rating /10	Latest Season Rating /10	Pilot episode IMDb rating /10	Most recent episode IMDb rating /10	*Average rating decline per episode
Westworld	2016-2022	8.9	8.0	8.8	7.0	-0.028
Game of Thrones	2011-2019	9.0	6.4	8.9	4.0	-0.014
The Crown	2016-ongoing	8.5	7.9	8.2	7.4	-0.012

*Rating decline figure based on the average decline in episode ratings across the whole series Please find the full dataset used in the study here.

TV shows that got worse over time

1. Westworld

Peak episode: 1×10 – The Bicameral Mind

Worst rated episode: 4×08 – Que Será, Será

RANT Casino revealed Westworld as the TV series that took the biggest downturn in ratings during its air time. The dystopian series is set in a Wild West-themed amusement park, with the pilot episode rated 8.8/10 on IMDb. However, across the show’s four seasons, episode ratings started to fall, declining by -0.028 per episode.

To make matters worse for the show, the final ever episode, titled Que Será, Será, is the lowest rated episode of all at 7.0/10. The finale of season one, which was Westworld’s peak episode, is The Bicameral Mind, with an IMDb rating of 9.7/10.

2. Game of Thrones

Peak episode: 3×09 – The Rains of Castamere

Worst rated episode: 8×06 – The Iron Throne

Coming in second is Game of Thrones (GoT). Based on the ‘A Song of Ice and Fire’ book series, with a fantasy backdrop of dragons and warfare over the Iron throne, this series took the world by storm. A total of eight seasons aired and the initial episode received a high rating of 8.9/10 from viewers. However, by the time the TV adaptation hit its fifth season, the storylines started moving away from that of the book series, and it saw the ratings plummet. 

The show struggled to recover from this, and by the time the final season aired most fans had lost faith. The highly anticipated final episode, The Iron Throne ended up being the lowest-rated episode of all, receiving an IMDb rating of just 4/10. In spite of this, the series overall downward trend stands at just -0.014, with several highly rated episodes balancing it out.

Season 3, Episode 9 The Rains of Castamere, is the show’s highest-rated episode, rated a whopping 9.9/10. 

3. The Crown

Peak episode: 3×03 – Aberfan

Worst rated episode: 5×10 – Decommissioned

The Crown comes in at third place. The historical drama centres around the reign of the late Queen Elizabeth II. The first season had great success with the pilot episode receiving an IMDb rating of 8.2/10. However as the show has progressed, ratings have taken a hit, with the latest season to air on Netflix suffering the worst ratings. 

Season 5, episode 10 titled; Decommissioned received an IMDb rating of 7.4/10. Currently the average downward rating trend of The Crown stands at -0.012 with the final season due to air in the autumn. There has already been a lot of talk in the media around what will be included in season 6, so there could be hope for a turnaround on ratings yet.  

The Crowns peak episode, Aberfan, episode 3 of season 3 saw its highest rating of 9.3/10 – which sees tragedy strike in the Welsh town of Aberfan, based on true events. 

Methodology:

• RANT Casino sought to find out which TV series got better and which got worse with time.
• A comprehensive seed list of 14 popular series from the past 5 to10 years was compiled utilising IMDb and Reddit.
• Following this, the ratings for each episode were scraped from IMDb.
• For each show, the 3-episode moving average was calculated as the average of the previous three episodes. This was used to determine where a show ‘peaks’ and where it ‘falls’.
• Additionally, the moving-average delta was calculated as the difference between each 3-episode moving average.
• An average rating for each season was also calculated for all shows and a formula was used, where if the trend was > 0.01 the show got better over time, if it was < -0.01 it got worse, otherwise stayed the same.
• This data was updated June 2023 and is subject to change.