Gross production average

Gross production average (GPA) is a baseball statistic created in 2003 by Aaron Gleeman,[1] as a refinement of on-base plus slugging (OPS).[2][3] GPA attempts to solve two frequently cited problems with OPS. First, OPS gives equal weight to its two components, on-base percentage (OBP) and slugging percentage (SLG). In fact, OBP contributes significantly more to scoring runs than SLG does. Sabermetricians have calculated that OBP is about 80% more valuable than SLG.[4][5] A second problem with OPS is that it generates numbers on a scale unfamiliar to most baseball fans. For all the problems with a traditional stat like batting average (AVG), baseball fans immediately know that a player batting .365 is significantly better than average, while a player batting .167 is significantly below average. But many fans do not immediately know how good a player with a 1.013 OPS is.

The basic formula for GPA is:[4] ${\displaystyle {\frac {{(1.8)OBP}+SLG}{4}}}$

Unlike OPS, this formula both gives proper relative weight to its two component statistics and generates a number that falls on a scale similar to the familiar batting average scale.[6]