Inferential and sensitivity studies of the baseball wins above replacement metric

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Conference Proceeding

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The Wins Against Replacement (WAR) metric for player evaluation, although widely used by fans and organizations, has not been closely studied. Although there are several competing versions of the metric, each using different weights for the various components, inferential comparisons of the versions have not been undertaken previously. Additionally, the sensitivity of the metrics to the weights has not been explored. The present study compares the various versions, both by considering the ability of WAR to predict actual wins and by comparing the assignment of values to players. We found no significant differences among several of the most common versions. We also tested the sensitivity of WAR to changes in the weights used and found that even extreme changes in weights have relatively little effect, indicating that the metrics are relatively insensitive to the details of the weighting. These results help to identify limitations of the current WAR metric and indicate potential extensions of the metric.


Presented at the Eighth Annual Conference of the Upstate Chapters of the American Statistical Association in Rochester, New York, April 27, 2019.

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