A Goal for Pitchers

A common idea is that successful pitchers stay ahead on the count.  That means pitching more strikes than balls.  It has been suggested by some baseball coaches that a pitcher should strive to pitch 60% strikes.  I collected some data from the recent International Softball Federation World Tournament that confirmed this suggested goal for pitchers.

I wanted to answer the question: how important is it to pitch a high percentage of strikes?  I found data from Major League Baseball on this subject.  There were 88 pitchers in the sample.  The average strike percentage was 64.0% and the average earned run average was 3.87.

I did a linear regression to determine the relationship between strike percentage and earned run average.  The significance of the relationship was very high.

The regression equation I found is:

Earned run average = 12.5 – 13.5 * strike percentage

Here are some predicted values for earned run average based on strike percentage using this equation.

Strike Percentage	Earned Run Average
70%	3.06
65%	3.73
60%	4.41
55%	5.08
50%	5.76

From these results, I can see why coaches recommend that pitchers strive to throw at least 60% strikes.