Intro to Sabermetrics: wRC+
A few weeks ago we started a series where we take a look at some sabermetric stats and concepts, and how they apply to the Orioles. The first entry in the series focused on wOBA, which is a primary crux of offensive value according to sabermetrics. This entry will focus on another offensive stat: wRC+.
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Weighted Runs Created Plus (wRC+) is a stat that builds on wOBA and provides a bit more context to a given player’s offensive output. wRC+ is an index stat, so league average is scaled to 100 with each point above or below 100 representing the same percentile above or below league average. So far this season Travis Snider has a 114 wRC+ which can be interpreted as Snider’s offense being 14% better than league average.
Part of the beauty of wRC+ is that it’s both park and league adjusted, so it allows for quick and easy comparison of players across eras. If you want to know how much better Eddie Murray was offensively than Adam Jones, then a quick comparison of their wRC+ allows you to do that. Over his career Murray was 27% better than league average, good for a 127 wRC+. Jones hasn’t been quite as good over his career, but his 111 wRC+ shows that he is an above average offensive player.
In terms of calculation, wRC+ can be done two ways. The quick and dirty method gives you a non-adjusted result:
wRC = (((wOBA-League wOBA)/wOBA Scale)+(League R/PA))*PA
That method will give you good approximation of offensive value, but the stats you’ll find online will be both park and league adjusted, which requires a bit more calculation:
wRC+ = (((wRAA/PA + League R/PA) + (League R/PA – Park Factor* League R/PA))/ (AL or NL wRC/PA excluding pitchers))*100
The calculation seems intense, but it’s easily do-able on a graphing calculator or an excel spreadsheet.
The benefit of wRC+ over wOBA is that it adjusts for the context within which a player plays. In doing so it tells you how much more impressive Justin Upton’s season (.392 wOBA, 157 wRC+) has been than D.J. LeMahieu’s (.410 wOBA, 148 wRC+), despite LeMahieu having a better batting line to date.
Now we have a good idea of the advantages of wRC+, how have the O’s performed through the eyes of this stat? Adam Jones’ 2015 has been nuts, his wRC+ of 200 suggesting he’s been twice as good as a league average htiter this season. Jones’ isn’t the only hot oriole so far in 2015 though. Three Oriole infielders have been at least 50% better than league average as well. Paredes (183 wRC+), Flaherty (174), and Jonathan Schoop (156) have all started out strong this season, giving the O’s more difficult decisions at second base.
The biggest disappointments this season have easily been Alejandro De Aza (75) and Steve Pearce (54). Both guys are well below average offensively at this point, which is made all the more clear when looking at wRC+ rather than a traditional batting line. Both guys were expected to be a big part of the O’s offense this year, so the club will need them to pick things up or they’ll have to look elsewhere for more offense out of their respective positions.
wRC+ helps give a snapshot of a player’s total offensive performance in context, something that’s extremely valuable when looking to compare players across the league. For the O’s, the season is still young, but wRC+ can give us an idea of which players truly are swinging hot bats vs. the ones who have started off cold this season. As the season continues, wRC+ will be an interesting lens through which we can observe the team’s offensive performance over the course of the season.
If you’re interested in comparing last year’s club versus this year’s team, the requisite leaderboards can be found below:
Thanks to Neil Weinberg and the excellent FanGraphs library for assistance in writing this overview.