ERA

Erik,

One of these days you're going to have to give me a lesson on the earned run average. The batting average I grok: the higher the better. Is the opposite true for ERA? Am I looking for a low number?

Pitching has always been thought of as an art, in contrast to hitting, which has generally been considered a science.
The Art of Pitching: The Pitcher Register, The Baseball Encyclopedia, 2004 edition

I ask because I ran to my Baseball Encyclopedia (all 1,697 pages of which I got for $4.99 at a Borders in Scottsdale) to look up facts about Zambrano. His ERA across 3 seasons with Chicago averaged 3.57. I didn't understand. To compare, I flipped to Randy Johnson, who over 16 seasons touts 3.10. Kerry Wood, 3.62 over 5 seasons. Jason Schmidt, 4.02 over 9 seasons. Roger Clemens, 3.19 over 20 seasons.

I sooooo don't get it. Help!