IBB Decision Grader
Every intentional walk raises the batting team's run expectancy. We ask whether the matchup advantage gained — bypassing a dangerous batter to face a weaker one — exceeded that cost. Graded against RE24 break-even using season wOBA for both the walked batter and the on-deck hitter.
Key finding: 97.5% of intentional walks (2020–2026) were value-negative: the run-expectancy cost of adding a baserunner (avg +0.17 RE) almost always exceeded the matchup gain from bypassing the walked batter. The average IBB costs the issuing team about 0.14 expected runs. This is consistent with the sabermetric consensus — and explains why IBB usage has fallen 45% since the 2017 automatic-walk rule.
IBBs graded (2020–2026)
3,124
Across 209 team-seasons
Good IBB rate
2.5%
Only 79 of 3,124 IBBs were value-positive
Avg RE cost per IBB
+0.17
Expected runs added to batting team
Avg run value per IBB
-0.14
Net run cost to issuing team
By team-year
About these grades
Each IBB is graded by comparing the matchup advantage gained (walked batter's wOBA vs. on-deck batter's wOBA, scaled by 1/wOBA_scale) against the RE24 run-expectancy cost of the intentional walk. Batter wOBA is computed from season Statcast data; batters with fewer than 50 PA use league average. Entries marked Low have fewer than 20 IBBs and carry higher uncertainty. 2020 entries are flagged 60g. Entries marked Live are from the current in-progress season. Full methodology