Wenz: Declaring openWAR
From Michael Wenz at Baseball Prospectus on January 4, 2016, with mention of SABR member Ben Baumer:
Caught Looking examines articles from the academic literature relevant to baseball and statistical analysis. This review will cover openWAR: An open source system for evaluating overall player performance in major league baseball, by Benjamin Baumer, Shane Jensen and Gregory Matthews in the June 2015 Journal of Quantitative Analysis in Sports. The goal, as always, is to expose the academic frontier to a wide audience and seek ways to move the discussion forward.
Most baseball statistics are easy to define—a run scored is a run scored. Sometimes a bit of judgment goes into the definition—sacrifice flies appear in the denominator for on-base percentage but not batting average, for instance—but the definition is at least widely agreed on. Wins Above Replacement (WAR), however, is a statistic that involves much judgment and little agreement. Baseball Prospectus publishes a measure called WARP, and FanGraphs (fWAR) and Baseball-Reference (bWAR) have measures of their own. In a recent paper, Benjamin Baumer, Shane Jensen and Gregory Matthews have declared openWAR on the others.
Their paper, openWAR: An open source system for evaluating overall player performance in major league baseball, proposes a new manifestation of WAR that is different from the other measures in some important ways. They also emphasize reproducibility, and along with their paper, the authors make available an R software program that allows users to recreate their work. Reproducibility and transparency have become increasingly important topics in academic research in recent years, and meeting very exacting standards for reproducibility is one of the authors’ stated goals. This stands in contrast to existing methods that rely on proprietary methods and opaque calculations. Whether their method outperforms the other measures is, of course, an open question and a difficult one to answer.
Read the full article here: http://www.baseballprospectus.com/article.php?articleid=28142
Originally published: January 4, 2016. Last Updated: January 4, 2016.