Gross production average

Gross production average (GPA) is a baseball statistic created in 2003 by Aaron Gleeman,{{Cite web |url=http://aarongleeman.com/2003_11_23_baseballblog_archive.html |title=Archived copy |access-date=2011-11-06 |archive-url=https://web.archive.org/web/20111015034953/http://www.aarongleeman.com/2003_11_23_baseballblog_archive.html |archive-date=2011-10-15 |url-status=dead }} as a refinement of on-base plus slugging (OPS).{{cite web|url=http://www.hardballtimes.com/main/article/about-those-stats/|title=About Those Stats…|date=3 May 2004 |publisher=}}{{cite web |url=http://www.aarongleeman.com/2003_11_23_baseballblog_archive.html |title=Archived copy |accessdate=2009-03-25 |url-status=dead |archiveurl=https://web.archive.org/web/20081210132820/http://www.aarongleeman.com/2003_11_23_baseballblog_archive.html |archivedate=2008-12-10 }} 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.{{cite web|url=http://www.hardballtimes.com/main/statpages/glossary/#gpa|title=Glossary – The Hardball Times|publisher=}}{{cite web|url=http://www.hardballtimes.com/main/article/about-those-stats|title=About Those Stats...|date=3 May 2004 |publisher=}} 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: $\backslash frac\{\{(1.8)OBP\}\; +\; SLG\}\{4\}$

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.{{cite web|url=https://www.nytimes.com/2007/02/25/sports/baseball/25score.html|title=New Baseball Statistic, With a Nod to an Old Standard|date=25 February 2007|work=The New York Times}}