Age Productivity Charts
This is just a little research piece, nothing really. For research that I am hoping to do later, I needed an answer to questions of this nature:
If a player is active and in the major leagues at ages 25 and 34, how likely is it that he is more valuable at age 25 than at age 34?
I considered all players to be eligible for the study who (a) batted 400 or more times in a season (b) between 1900 and 2017. This excludes (most) players from 1981 and 1994, for example, but that doesn’t matter. Those who aren’t in the study don’t influence the conclusion of the study.
The exact answer to that question is that there were 333 players who had 400 or more plate appearances in a season at age 25 and also at age 34. Of those 333 players, 214.5 were credited with more Win Shares at age 25 than at age 34, and 118.5 were credited with more Win Shares at age 34 than at age 25. If a player had the same Win Shares both seasons, he was counted as .50 on each side of the ledger. 64% (almost 65%) of those players had more value at age 25 than at age 34.
That’s non-pitchers. Among pitchers, there were 265 players who had 54 or more game appearance points both at age 25 and at age 34. 160.5 of those had more value at age 25 than at age 34, and 104.5 had more value at age 34 than at age 25. That’s a 61-39 split. Game Appearance points is (Games + Games Started), a common reference point. I guess we’ll have to modify it if the 2-inning-starts thing catches on. If you have 27 games, all of them starts, that’s 54; if you have 54 relief appearances and no starts, that’s 54. If you have 40 games appearances/14 starts, that’s 54. I chose 54 because it is the number that is most comparable to 400 plate appearances.
And, of course, I didn’t just do 25 and 34, I did 20 and 21, 20 and 22, 20 and 40, 26 and 42. . . .any possible combination of numbers between 17 and 48.
If you compare 21-year-olds to 22-year-olds, you have 188 comparisons, 188 players (non-pitchers) who had 400 plate appearances at both ages. If you compare 22-year-olds to 23-year-olds, you have 374 comparisons. I decided that any number less than 200 would be considered unreliable, and any number over 200 would be considered reliable. These, then, are the percentages for each age-to-age comparison, when there were 200 comparisons in the group:
|
22
|
23
|
24
|
25
|
26
|
27
|
28
|
29
|
30
|
31
|
32
|
33
|
34
|
35
|
36
|
22
|
50%
|
61%
|
66%
|
63%
|
61%
|
62%
|
62%
|
61%
|
55%
|
56%
|
|
|
|
|
|
23
|
39%
|
50%
|
58%
|
56%
|
59%
|
57%
|
53%
|
51%
|
55%
|
47%
|
42%
|
41%
|
|
|
|
24
|
34%
|
42%
|
50%
|
54%
|
56%
|
56%
|
53%
|
52%
|
48%
|
47%
|
41%
|
39%
|
43%
|
|
|
25
|
37%
|
44%
|
46%
|
50%
|
53%
|
52%
|
49%
|
47%
|
47%
|
44%
|
40%
|
33%
|
36%
|
31%
|
|
26
|
39%
|
41%
|
44%
|
47%
|
50%
|
49%
|
46%
|
45%
|
44%
|
40%
|
37%
|
32%
|
32%
|
31%
|
19%
|
27
|
36%
|
43%
|
44%
|
48%
|
51%
|
50%
|
45%
|
44%
|
41%
|
38%
|
37%
|
33%
|
31%
|
26%
|
24%
|
28
|
38%
|
47%
|
47%
|
51%
|
54%
|
55%
|
50%
|
46%
|
45%
|
43%
|
37%
|
33%
|
32%
|
27%
|
25%
|
29
|
39%
|
49%
|
48%
|
53%
|
55%
|
56%
|
54%
|
50%
|
44%
|
45%
|
34%
|
32%
|
31%
|
27%
|
24%
|
30
|
45%
|
46%
|
52%
|
53%
|
56%
|
59%
|
55%
|
56%
|
50%
|
45%
|
39%
|
35%
|
33%
|
24%
|
21%
|
31
|
44%
|
53%
|
53%
|
56%
|
60%
|
62%
|
57%
|
55%
|
55%
|
50%
|
41%
|
35%
|
31%
|
25%
|
23%
|
32
|
|
58%
|
59%
|
60%
|
63%
|
63%
|
63%
|
66%
|
61%
|
59%
|
50%
|
39%
|
34%
|
28%
|
24%
|
33
|
|
59%
|
61%
|
67%
|
68%
|
67%
|
67%
|
68%
|
65%
|
65%
|
61%
|
50%
|
42%
|
37%
|
32%
|
34
|
|
|
57%
|
64%
|
68%
|
69%
|
68%
|
69%
|
67%
|
69%
|
66%
|
58%
|
50%
|
36%
|
36%
|
35
|
|
|
|
69%
|
69%
|
74%
|
73%
|
73%
|
76%
|
75%
|
72%
|
63%
|
64%
|
50%
|
41%
|
36
|
|
|
|
|
81%
|
76%
|
75%
|
76%
|
79%
|
77%
|
76%
|
68%
|
64%
|
59%
|
50%
|
Helping you to read the chart, because it would take you four seconds to figure it out on your own. . . .of the players who were in the study both at age 22 and 23, 61% were better at age 23 than at age 22, and 39% were better at age 22 than at age 23. Comparing 26 year olds and 36 year olds, 81% were better at age 26 than at age 36, and 19% were better at age 36 than at age 26.
Those are the numbers for batters; these are the numbers for pitchers:
|
22
|
23
|
24
|
25
|
26
|
27
|
28
|
29
|
30
|
31
|
32
|
33
|
34
|
35
|
36
|
37
|
22
|
50%
|
55%
|
56%
|
61%
|
63%
|
59%
|
|
|
|
|
|
|
|
|
|
|
23
|
45%
|
50%
|
46%
|
51%
|
50%
|
48%
|
49%
|
46%
|
46%
|
50%
|
|
|
|
|
|
|
24
|
44%
|
54%
|
50%
|
50%
|
52%
|
52%
|
49%
|
49%
|
49%
|
48%
|
43%
|
47%
|
|
|
|
|
25
|
39%
|
49%
|
50%
|
50%
|
49%
|
50%
|
47%
|
48%
|
46%
|
44%
|
45%
|
41%
|
39%
|
|
|
|
26
|
37%
|
50%
|
48%
|
51%
|
50%
|
47%
|
47%
|
46%
|
45%
|
41%
|
40%
|
41%
|
43%
|
39%
|
|
|
27
|
41%
|
52%
|
48%
|
50%
|
53%
|
50%
|
46%
|
49%
|
46%
|
46%
|
44%
|
40%
|
41%
|
40%
|
|
|
28
|
|
51%
|
51%
|
53%
|
53%
|
54%
|
50%
|
45%
|
46%
|
43%
|
40%
|
39%
|
41%
|
41%
|
36%
|
|
29
|
|
54%
|
51%
|
52%
|
54%
|
51%
|
55%
|
50%
|
46%
|
45%
|
42%
|
36%
|
42%
|
40%
|
34%
|
|
30
|
|
54%
|
51%
|
54%
|
55%
|
55%
|
54%
|
54%
|
50%
|
47%
|
42%
|
35%
|
41%
|
40%
|
38%
|
|
31
|
|
50%
|
52%
|
56%
|
59%
|
54%
|
57%
|
55%
|
53%
|
50%
|
40%
|
39%
|
42%
|
40%
|
37%
|
|
32
|
|
|
57%
|
55%
|
60%
|
56%
|
60%
|
58%
|
58%
|
60%
|
50%
|
44%
|
39%
|
45%
|
38%
|
|
33
|
|
|
53%
|
59%
|
59%
|
60%
|
61%
|
64%
|
65%
|
61%
|
56%
|
50%
|
43%
|
43%
|
38%
|
|
34
|
|
|
|
61%
|
57%
|
59%
|
59%
|
58%
|
59%
|
58%
|
61%
|
57%
|
50%
|
42%
|
42%
|
|
35
|
|
|
|
|
61%
|
60%
|
59%
|
60%
|
60%
|
60%
|
55%
|
57%
|
58%
|
50%
|
39%
|
|
36
|
|
|
|
|
|
|
64%
|
66%
|
62%
|
63%
|
62%
|
62%
|
58%
|
61%
|
50%
|
40%
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
60%
|
|
As you can see, the data for pitchers is quite a bit different than the data for non-pitchers. Pitchers have much less predictable career paths than hitters. There are 188 entries on the hitters chart, of which exactly half—94—are either 60 or higher or 40 or lower. But on the pitchers charts, there are 170 entries, of which only 46 are 60 or higher or 40 or lower. Whereas it is unusual for a hitter to have a better year at 36 than he did at age 26—only 19% of players did this—it is much more common for pitchers; 39% of pitchers had better seasons at age 36 than at 26 (70.5 of 179.) And whereas only 4% of hitters had better seasons at age 40 than they had at age 31 (1.5 out of 40), 29% of pitchers did this (20 out of 70.) Just totally different career paths.
Well. . . a lot of things to do with regard to these charts, but I’ll get to that. Just wanted to share the charts with you, and then get back to the pitcher stuff that I was doing before.