Note RPG is Runs Per Game, and is based my formula discussed in a previous blog post.
I love the work of Bill James, but I believe that this is one of the dumbest things that he has ever said. I believe that he is correct about the distribution of talent of players in the major leagues, and yet I believe that baseball talent is distributed normally FOR HUMANS ON EARTH. In fact, if you pay players millions of dollars to play a game that is considered fun so that almost any person on earth who could play the game would want to, what you will end up with is a group of people who were +4.25 on the normal curve. What, if this were true, would the talent distribution look like in major league baseball (or any other sport where the players are paid millions of dollars for that matter) look like? It would look like a pyramid. For every player who was 10 percent above average, there would be 20 players who were 20 percent below average. The fact that this is true does not dispute that baseball talent is normally distributed (among humans on earth), it helps to prove it.
Here is the Distribution of Batting RPG using my Formula. It batters from 1981-2013 with more than 250 At Bats and are not Pitchers.
Here is the same formula with a trend line-like formula going from 4.5 standard deviations to 5.29 standard deviations starting at the highest point on this chart.
There is not the hard cut off one might expect and hope for, but players play hurt, managers and GMs are not perfect judges of talent, players don’t play up to their talent level due to chance. Also, this is just batting that the players are being rated on. Some of the players below the .5 RPG mark are Mark Belanger and Ozzie Smith. The Max distribution is at .5 RPG, and is players with .5 and .51 runs per game. There are 271 Player seasons at that level, 5099 above it and 3155 below that point. It looks a little “normal-y” but I stand by Bill Jame’s analysis and my own.
If you want to see something that looks a bit more like a normal distribution look at RPG for pitchers all time: