FanPost

Age in the NBA


This isn't necessarily specific to the Wizards, but it's important for this team considering their current roster as the team contemplates how long they should give their current roster to "win-now".  My past experience following players has told me that players decline faster than conventional wisdom seems to indicate. I think John Hollinger may have actually sorted this out already, but I can't find his age trajectory published free anywhere so I don't know for sure. So, I tried compiling some data to figure this out on my own.  I figured out that this is a bit more complicated than I originally thought.  However, in the end the data clearly indicated that players peak at ages 25-27, and decline significantly after age 30.  I'll explain why below the jump.

What I did to figure this out was compile average stats per 36 minutes by age for the 2000-2007 seasons of all players totaling 400 or more minutes (an arbitrary number, but I figured less than 10 minutes per game for less than 40 games shouldn't count). What I found was that there is a selection bias at the very early ages and very late ages (i.e. only better players get significant burn in the NBA before age 23 or after age 34). This makes it difficult to draw the curve we all know should be there (especially those of us over 30).  What turned out to be the best indicator was the actual number of player-seasons for each year of age.  Presumably, there will be the most players at the peak playing age, with less at pre- and post-peak ages. (If you're just barely good enough to make it in the NBA, you'll only be there in your best years.) This qualification aspect, combined with the per-minute stats indicate that players start declining after age 27, and that the decline accelerates after age 30. 

To illustrate the point, you can see in the table below that there are 2.6 times as many 27-year-old player-seasons as 33-year-old player-seasons (whose stats are significantly worse despite the fact that it was likely the weaker players making up most of the 60% whose careers ended between ages 27 and 33). 34-year-olds look the worst, statistically, as after that the selection bias overwhelms the decline.

If you all are interested in seeing this broken out by position (G/F/C), let me know.  Now that I have the data set up it won't be hard to redo this.

Here's the table: (for you non-stat-geeks, 'n' means sample size, meaning number of player-seasons, )

Age      n          Pts       Reb      Ast       Stl        Blk       TO       PF        Pts/Shot

19        33        13.4     6.8       2.3       1.0       1.1       2.2       3.8       1.16

20        79        13.1     6.6       2.7       1.1       1.0       2.2       3.8       1.17

21        126      14.0     6.4       2.9       1.2       0.9       2.3       3.7       1.18

22        198      14.0     6.3       2.8       1.2       0.8       2.2       3.6       1.20

23        240      13.8     6.4       2.7       1.1       0.8       2.2       3.8       1.19

24        254      14.1     6.4       2.8       1.1       0.8       2.1       3.6       1.20

25        273      13.9     6.4       2.9       1.1       0.8       2.1       3.5       1.18

26        270      14.3     6.2       3.1       1.1       0.7       2.1       3.4       1.19

27        265      14.2     6.3       2.9       1.1       0.8       2.1       3.5       1.19

28        218      13.9     6.2       3.1       1.1       0.7       2.0       3.5       1.20

29        201      13.3     6.1       3.1       1.1       0.7       2.0       3.5       1.18

30        206      13.3     6.1       3.0       1.1       0.7       2.0       3.5       1.19

31        165      13.2     6.0       3.4       1.1       0.6       2.0       3.4       1.16

32        142      12.2     5.9       3.2       1.1       0.6       1.9       3.3       1.16

33        106      11.6     6.0       3.4       1.1       0.6       1.9       3.2       1.13

34        105      11.0     6.0       3.4       1.1       0.6       1.9       3.4       1.11

35        72        11.2     6.3       3.0       1.1       0.8       1.8       3.4       1.15

36        39        11.1     5.6       3.5       1.1       0.7       1.9       3.2       1.13

37        30        11.4     6.2       3.3       1.1       0.7       2.0       3.4       1.14

38        27        12.5     6.3       3.6       1.3       0.7       2.1       3.4       1.13

39        11        12.7     7.1       3.0       1.2       0.7       1.9       3.6       1.26

40        5          11.1     8.1       3.5       1.1       0.9       2.1       3.8       1.27

41        1          6.9       11.6     0.3       0.6       2.8       1.0       3.2       1.48

This represents the view of the user who wrote the FanPost, and not the entire Bullets Forever community. We're a place of many opinions, not just one.

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