"Tom Seaver's better than Ron Guidry!" shouted Paul. "No he isn't," replied Nancy quickly. "Guidry's the greatest pitcher in baseball!"
"Oh, you're just a girl. How would you know?" sneered Paul.
"Compare their ERAs," Nancy said calmly.
Ever heard an argument like that? Ever been in one? If so, you might need to know what an ERA is and how you calculate it.
ERA stands for earned-run average. It is generally considered the best measure of a pitcher's ability, just as a batting average is for a hitter.
To determine a pitcher's ERA you first find out the number of earned runs he has given up. An "earned run" is on that the batting team scores without the benefit of an error by the team that is in the field.
Take a pitcher named "Fireball Frank." Let's say that in Game 1 he gave up 2 runs. In Game 2 he allowed 4 runs, and the other team scored twice on errors. In Game 3 the opposing team scored twice, and there were no errors. Game 4 was a shutout, no runs scored by the other team, but in Game 5 "Fireball" was clobbered by the opposing batters for 6 runs in less than four innings. So let's add those up:
Game 1 -- 2 earned runs
Game 2 -- 4 earned runs
Game 3 -- 2 earned runs
Game 4 -- 0 earned runs
Game 5 -- 6 earned runs
That's a total of 14 runs.
The next step is to find out how many innings a pitcher has pitched. Suppose that in his first game "Fireball Frank" hurled 9 innings. In his second game he was taken out with two men but in the eighth inning, having completed 7 2/3 innings. In his third pitching effort he was removed for a pinch hitter after 7 full innings. In his fourth game he went a full 9 innings, but in Game 5 he was removed with only one man out in the fourth inning, having pitched 3 1/2 innings. Let's add up the innings pitched:
Game 1 -- 9
Game 2 -- 7 2/3
Game 3 -- 7
Game 4 -- 9
Game 5 -- 3 1/3
The total is 36 innings pitched.
Now we have 14 runs for 36 innings pitched. The last step is to multiply the number of runs, 14, times 9 (the number 9 is used because nine innings equals a full game) and divide that total by the number of innings pitched, 36. Here is the result: 14 times 9 is 126, and 126 divided by 36 is 3.50. That's "Fireball Frank's" ERA.
Figure out "Slim Jim's" ERA for yourself. Get a pencil and paper and follow these steps:
1. Add up the number of earned runs.
2. Multiply that total by 9.
3. Add up the number of innings that Jim pitched.
4. Divide the number you got in Step 2 by the number you found in Step 3. The result is "Slim Jim's" ERA.
Game 1 -- "Slim Jim" went 2 innings and allowed 1 run.
Game 2 -- He went 7 innings and allowed 4 runs, but the other team also scored once on an error.
Game 3 -- He went 6 1/3 innings and allowed 2 runs.
Game 4 -- He went 2 2/3 innings and allowed 6 runs.
Game 5 -- He went 9 innings and allowed 3 runs.
What's his ERA? Who's the better pitcher, "Slim Jim" or "Fireball Frank"? Answer
Frank is the better pitcher because he allowed an average of only 3.50 runs per game. Jim's ERA is 5.33.