NBA team performance over 40 seasons

Watching the Bulls documentary on Netflix, I was curious how NBA teams performed over many seasons. I could not quite find this in ready form so I had to create it myself.

I scraped Basketball Reference to get regular season stats (1980–2019). It should be a good proxy for overall season performance.

The code can be found on Github. The visualisation script is in written in R.

I calculated a few metrics: total number of wins, win percentage and the mean rank (across seasons). I was surprised to find that the Spurs actually come first in terms of games won, the top 10 below is sorted by win percentage. Bulls doesn’t even feature here.

team     wins win_pc  mean_rank
   <chr> <dbl>  <dbl>     <dbl>
 1 SAS    2018  0.624      7.42
 2 LAL    1969  0.609      8.82
 3 OKC     538  0.607      9.09
 4 BOS    1855  0.574     11.0 
 5 POR    1812  0.561     11.2 
 6 UTA    1803  0.558     11.2 
 7 HOU    1802  0.558     10.9 
 8 SEA    1284  0.547     12.4 
 9 PHO    1759  0.544     12.4 
10 MIA    1294  0.519     13.6

The chart below shows the win percentage across seasons for the top 7 teams. It’s interesting to see how low some teams can actually drop. Getting above 80% is quite rare.

Here is the same chart for some well known franchises, including Bulls.

Here is the same set but this time we have the rank.