from Amazon
Thursday, April 10, 2008
Peak ages for hitters and pitchers
Clay gives us a very simple method to figure a player’s peak age. Look at the age of his peak! Instead of all the rigamorole that most of us do, by trying to figure out the trajectory of a player’s performance, and then inferring the peak point from that, Clay simply counts the age of the peak performance for each player (with the result that he won’t know the trajectory). Good job.
There is a sampling bias of course. A good player will get a chance to peak in his 30s, simply by being given the opportunity to do so. A bad player won’t: he might “peak” at age 25, then be out of baseball by age 27, when in fact, if he was given the opportunity to continue to play until 43, he might have had a better season at some point over those next 16 years, just by luck.
Solution? Here’s one. Use the same age period for each player. Look at players’ career only from age 23 to 30 (and if they played in each of those seasons). Then, look from age 25 to 32. And from 27 to 34. If they TRULY peak at age 26 or 27, then we should see it in all these groupings.
Yeah, that solution sounds good because players like Utley and Howard were not called up until later in years, so they would appear to peak at 29-30 whereas it’s actually only their third or fourth year in the league.... a guy like David Wright may peak at 26 or 27 which would be younger than the two Phillies but consist of equal or more service time.