wRAA → wRC+: from rate to runs to the 100 scale
'He created 20% more offense than an average hitter, anywhere, any era.' One number says that.
wOBA is a rate. Subtract league average, scale by plate appearances, and you get wRAA — actual runs added versus an average hitter. A +30 wRAA season means his bat put ~30 extra runs on the board.
Then adjust and rescale
Apply park factors (Level 2), compare to the league's run environment, put it on the 100 scale, and you have wRC+ — the headline number of modern hitting analysis. 100 = average, 150 = 50% better than average, 80 = fringe starter. Every serious 'best hitter' argument today is a wRC+ argument.
Note the pedigree: run values (L3.1) → wOBA (L3.2) → wRAA → park adjustment (L2) → 100 scale (L2). Nothing was new here — you already knew every ingredient. StatLab shows OPS+ (same idea, cruder weights) where our sources provide it; the toggle between standards is coming as data allows.
The formula (optional — skippable)
wRAA = ((wOBA − lgwOBA) ÷ 1.24) × PA wRC+ = 100 × (adjusted runs per PA ÷ league rate)
1.24 ≈ the 'wOBA scale' converting wOBA points to runs.
How this stat lies to you
- Still bat-only: a 140 wRC+ DH and a 140 wRC+ shortstop are NOT equally valuable (Level 5).
- Park factors are estimates; extreme-profile hitters (fly-ball lefties, e.g.) can be over/under-corrected.
- Small samples still lie — a 200 wRC+ April is a hot month, not a true talent.
Check yourself
1. A hitter posts a 125 wRC+. Translation?
2. Why is wRC+ fairer than raw wOBA for comparing a Rockie and a Giant?