Run average is the number of runs allowed per inning pitched. Compared with ERA, it includes all runs against (including unearned runs).
A lower run average is seen as a better.
While it is primarily a pitching metric, it can also be used to evaluate a team’s defensive performance as a whole.
RA = Innings per Regulation Game x (Runs ÷ (Innings Pitched + (Outs (Partial Innings) Pitched / 3))
A pitcher has 69 runs allowed across 202 innings and 1 out pitched. The league they play in has a regulation time of 9 innings.
RA = 9 x (69 ÷ 202.333333)
RA = 9 x 0.3410
RA = 3.069
This pitcher’s run average 3.069, or an average of 3.069 runs allowed per 9 innings of play.