Wyers: Reworking Baseball Prospectus WARP

From SABR member Colin Wyers at Baseball Prospectus on August 21, 2013:

The hardest part of explaining sabermetrics to someone who’s versed in traditional baseball stats is explaining that they’re different not just in degree, but also in kind. The definition of an RBI, for instance, hasn’t changed since it was made an official statistic in 1920. The stats created by sabermetricians are much more prone to revision. Some look at this as a bug, because they view sabermetrics only as potentially better versions of traditional stats.

But sabermetrics isn’t ever a finished product. (This is not, in fact, a bad thing.) So instead of expecting our stats to calcify, we should be expecting them to grow and change as we develop the ideas beneath them. So it is with WARP, which has undergone any number of changes over the years. And now we’re going to be changing WARP again. But we’re going to be throwing open the doors and letting you watch us while we work. So we’re kicking off a series of articles, running each Wednesday, where we’ll take you inside what we’re doing. There’ll be a lot of math, but also a lot of discussion about what WARP is trying to measure and the philosophy behind various choices.

We hope this will do several things. We think that talking openly about what we’re doing will help us build better metrics, because we’ll be getting more feedback earlier in the process. And we think it will help you all to understand the metrics we’re building, because you’ll have more insight not only into what is being done, but why. And this is not a finished product—the goal of this series is to have readers looking over my shoulder as I work. If what you want is a final summation, that will be coming down the road. If you want to watch the development process at work, this is for you.

Read the full article here: http://www.baseballprospectus.com/article.php?articleid=21586

Originally published: August 21, 2013. Last Updated: August 21, 2013.