Age and Production (part 1)  (07/10/01)
 
 

Just before the season opened, I began a study to determine if there is a relationship between a player's age and his amount of production.  What I wanted to find out is whether or not the age when a player debuts is a future indicator of overall production and/or yearly production.

I went at the issue from 2 different angels.  In the first, I looked at the best players in history to see if any trend shows up.  For the second, I will look at all players to see if any of the distinctions that were found amongst the best players, were also found in the rest of the population.  I've just completed the first part of part 1: grading the top 500 hitters of all time using Total Player Rating as my primary metric.  This list includes active players.  Here're the initial results:
 
 

Debut Age	Total Years	Total TPR	TPR/Y	Peak Year
17-18	15.3	25.2	1.428	4.7
19	17.0	30.3	1.735	5.2
20	16.6	27.1	1.536	5.0
21	15.4	21.9	1.423	4.4
22	14.2	18.8	1.378	4.4
23	13.6	17.9	1.350	4.1
24	12.2	14.5	1.236	3.9
25	12.4	15.3	1.299	3.9
26+	11.1	15.4	1.338	3.9

Well, one could expect that the earlier that a player reaches the majors, the more years he's likely to play.  And for the most part that holds true.  Longevity would also logically be tied to a players total career production- the longer he played, the more productive his career was likely to have been.

What is interesting is the progression in average yearly production.  From ages 19 to 24, there is definitely a trend in increasing production the earlier a player gets to the majors.  That trend reverses after age 24, which might be due to the inclusion of imported players, like Negro Leaguers Jackie Robinson and Monte Irvin, who would have made the majors at a much earlier age had they been playing today, but came to the show later in life due to non-baseball related circumstances.

Anyway, there are two possibilities to explain the trend.  The first is that players that reach the majors younger simply have more years of peak production.  The second is that they actually have higher peaks of production.  So I took each player's peak year of performance and found an average peak value for players who came into the league at each age.  Much like the trend found in TPR/year, there is a distinct trend in the average peak year performances, with players who entered the league at 19 leading the way and a downward trend for later arrivals.

The jump from 18 to 19 is fairly intriguing.  One would expect, given the larger trend, that players who reach the majors by age 17 or 18 (I combined the two for a better sample size), would be the most productive on the list.  They were not.  They fell slightly behind the performances of players who reached the majors at age 20.  Several of these guys missed chunks of time due to various causes like wars.  But I suspect the main cause of their unexpected depressed numbers may be simply a case of them not being fully ready for the bigs and just not recovering from the negative experience.  Regardless, it's an interesting twist.

I haven't completed the top 500 pitchers or the rest of the population studies, but early indicators are that the same trends hold true, although much less demonstrably.

So far, it's looking very much that players who reach the majors at age 19 not only stand a better chance of having a long career than others, but that they will likely be the most productive players, both in terms of career totals and peak performances.  I'll post my other results as I finish them.
 

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