The Rise and Fall of the Individual Batting Average

Yes, it is that time of the year again - the start of the major league baseball season! Every April ignites that annual spark that lasts through World Series time in October. Although baseball is a team sport, a player's individual batting average often receives much attention from the press and the fans.

While growing up in Jamestown, NY, in the late 40's and early 50's, I was an avid baseball fan (and I still am). With the hometown Jamestown Falcons and the nearby Cleveland Indians and Pittsburgh Pirates, I often kept many batting-average statistics of the players on these teams. During the summer months, my brother Howard and I often listened to the Indians' or the Pirates' games and when a batter got a hit (or failed to get one), I would recalculate his average only if I knew the number of hits and the number of times at bat for that player.

My brother had a much easier method that did not use any of that information. If a player got a hit, he increased the players average by 2 points; otherwise, he decreased the average by 1 point. Why did Howard's method often work so well? As we develop some fundamental principles in this Pull-Out Section, we will see mathematically why his rules of thumb often worked so well and also when they don't work at all!