From SABR member Bill James at Bill James Online on November 4, 2019:
Regarding the Quality of Competition in Major League Baseball over time, one objective measure that we could get is the concentration of talent around the peak ages. The peak age for baseball player contributions, as we all know, is 27; actually, 26 and 27 are essentially equal. 26 measures as equal or slightly superior to 27 if you look at players who are established in the league by age 24 or 23 or 22 or something; 27 just measures as a little ahead of 26 in aggregate contribution because the process of players getting established in the major leagues is not 100% complete by age 26. At age 26, a small but not trivial number of players are still rookies or are still earning playing time.
Suppose that you look at teams selected from different ages, and for this thought experiment we do not rely on these being major league players. Suppose that we compare a team of 10-year-old players to a team of 13-year-old players. Who do you think will win?
Suppose that we compare a team of 16-year-olds to a team of 13-year-olds, or a team of 19-year-olds to a team of 16-year-olds. Of course we know that, up to a point, the older, more mature team will dominate.
Or suppose that we have a team of 70-year-olds playing a team of 60-year-olds, or a team of 70-year-olds playing a team of 80-year-olds. My point is that we know beyond any question that the closer a group of players is to the peak age, the stronger the team is likely to be. Also, we know from copious research that the peak age for a professional player is 26 to 27, although it is likely that the peak age for non-professional athletes is somewhat younger.
Read the full article here: https://www.billjamesonline.com/the_quality_of_competition_over_time/
Originally published: November 8, 2019. Last Updated: November 8, 2019.