wOBA (weighted On-Base Average) is the most predictive single hitter stat in modern baseball. It weighs each plate appearance outcome by its true run value, which makes it strictly better than batting average, OBP, or slugging for evaluating offense.
wOBA assigns each offensive event (walk, HBP, single, double, triple, HR) a weight based on its actual run-scoring value, then averages those weights per plate appearance. The formula varies slightly by year as run environment shifts, but a typical version: wOBA = (0.69×BB + 0.72×HBP + 0.89×1B + 1.27×2B + 1.62×3B + 2.10×HR) / PA.
The result scales like OBP. League-average wOBA is around .315-.325. Elite is .380+. Poor is below .290.
wOBA is THE modern triple-slash replacement. Every sharp baseball analytics framework uses it.
Lineup wOBA (sum or weighted average of starters' individual wOBAs) is one of the strongest predictors of team runs scored. Sharp models use:
wOBA measures what actually happened (outcomes). xwOBA measures what should have happened based on Statcast's quality-of-contact data (exit velocity + launch angle). xwOBA is even more predictive than wOBA because it strips out BABIP luck. Sharp models use both.
The lineup wOBA against the opposing starter's handedness is one of the model's primary offensive inputs. Combined with park factor and the starter's xERA, it produces the per-side expected run estimate that feeds the totals and run-line probability calculations.
Theory is one thing — using the concept on tonight's slate is the value. These hubs are the practical application: