In one season, it's straightforward: it shows who's on top and who's not, as any league should. But when we compare across seasons? That's where things get interesting.
Total points scored by all teams per season varies by year, with the core expected reason being the number of draws vs the number of wins per season. With a draw causing a total of 2 points compared to 3, 1 point is lost.
The alternative reason for total points loss is a point deduction, which occurred in the 2009/10 season with Portsmouth entering administration, and quickly being dragged all the way to League 2.
Three seasons stand out for their peaks: 18/19, 13/14, and 05/06. It’s also clear that since 09/10, there's been a noticeable upward trend, interestingly consistently zigzagging along the way.
If we plot histograms for points totals for these three standout reasons, we can see that they all share a pattern of a number of top teams being exceptional, although the points distributions between teams do still vary wildly.
There's a noticeable skew in the distribution towards higher goal differences, with a few teams having exceptionally high positive goal differences. The average goal difference is around 0, but the median is -4. This implies that while some teams had significantly positive goal differences (indicative of dominant performances), many teams had negative goal differences. City and Liverpool were outrageous this season
The distribution is fairly symmetric around zero, but there's a peak in the 40-50 goal difference range, suggesting one or more teams had dominant seasons. The average goal difference is slightly above 0, with a median of 0. This indicates a balanced league, but with a few standout performers. Chelsea under Morinho were nuts, Liverpool and United were both very strong teams.
An odd season, where 40 points would have left you very comfortably mid table, and in touching distance of the top half. This season contained an unusually high number of bad but not terrible teams. 2013/14 also saw Cardiff rightfully relegated for playing in a red kit.
This can be measured as the number of points that second place won over the season, though this isn’t a 100% fair representation. As shown by Man United in 2012, you can lose the league on goal difference.
Again this appears to be trending upwards over time, but is also more volatile than it was in the early 2000s.
The Leicester miracle is a notable low point, as is the 2010/11 season, which saw two teams relegated on 39 points, neither of which have since made it back to the top division (Blackpool and Birmingham)
The often said 40 points is pretty much bang on, though in the most extreme and unrealistic case, a team could get relegated on 63 points.
This would require the bottom 2 teams to lose all their games against the top 18. It would then require all other teams in the league to trade wins, leaving them each with 63 points, and relegating the team with the worst goal difference.
The only team to go down so far with greater than 40 points was West Ham in 2002/03, which in turn saw them lose plenty of household names to other Premier League teams (with losses including David James, Glen Johnson, Joe Cole, Michael Carrick, Jermain Defoe, etc)
While undulating, the number of points required to stay up seems mostly consistent. This season will surely be a low point, with a number of teams looking rubbish so far.
As bad as you’d expect. 30 points is regularly enough to ensure you don’t get the wooden spoon
I’ve got little to add here that’s not been said before, apart from the single goal in their 1-0 win against Newcastle really could have won goal of the season 2007-08 - Derby County 1 Newcastle United 0 - 17/09/2007
A truly shocking 15 points is often forgotten about in light of Derby’s embarrassment, but it shouldn’t be neglected.
Sunderland had been promoted as champions in the 2004-05 season under Mick McCarthy. Expectations were high, and there was a sense of optimism.
In the end they achieved 3 wins, though I believe they were lucky to get that many.