wOBA − xwOBA
Difference between actual and expected wOBA — large gaps suggest regression is coming.
What wOBA − xwOBA means
Positive gap = over-performing quality of contact (likely to cool off). Negative gap = under-performing (due for a bounce-back).
What counts as a good wOBA − xwOBA
Higher is better — roughly -.030 is poor, 0 average, .020 good, and .040 or better elite.
Also written
woba_minus_xwoba · gap_woba_xwoba