For starters, ERA stands for Earned Run Average. It is a common statistic found in baseball that represents the effectiveness of a pitcher. It is tracked over the course of nine innings, and a number is given to represent the value. The lower the ERA, the stronger the pitcher's performance is. For example, a premier starter in Major League Baseball that gives up two runs in nine innings pitched has a 2.00 ERA. Simple enough, right? Well, not every pitcher lasts nine innings a game (this is very rare), so ERA truly carries over to multiple games.