Does ABS behave differently in October?
Three things change in the postseason, all in the same direction: challenges come more often, they succeed more often, and the calls being overturned are bigger misses. None of it is yet separable from chance, because the postseason is 162 challenges against 10,546.
| Window | Games | Challenges | Overturn rate | Per game | Avg miss |
|---|---|---|---|---|---|
| Regular Season | 2,429 | 10,546 | 53.8% | 4.34 | 1.16" |
| Postseason | 35 | 162 | 60.5% | 4.63 | 1.45" |
| Wild Card Series | 9 | 41 | 58.5% | 4.56 | 1.13" |
| Division Series | 16 | 80 | 58.8% | 5.00 | 1.45" |
| League Championship Series | 10 | 41 | 65.9% | 4.10 | 1.80" |
| World Series | Not started | ||||
The gap, and whether to believe it
- Overturn rate
- +6.7 pts
- Challenges per game
- +0.29
- Average miss
- +0.29"
Not statistically significant at the conventional 95% threshold. A two-proportion z test on the overturn-rate gap gives z = 1.69, against the 1.96 needed. A +6.7 point gap on 162 challenges is the kind of difference a sample this small produces routinely. Treat it as a pattern worth watching, not a finding.
How these numbers are built
- Counts are ABS-only. Every figure counts ABS pitch challenges and nothing else. Manager challenges and fair-foul reviews are excluded, which is the same basis used everywhere else on the site.
- Per game uses games played. Challenges divided by completed games in that window, not by games that happened to produce a challenge.
- Average miss covers overturned calls only. Miss size is measured from the edge of the ball to the edge of the rule-book zone. It only means something for a call that was actually wrong, so confirmed calls are left out of that column.
- Rounds are MLB game types. Wild Card, Division Series, League Championship and World Series map to MLB's own game-type codes. Within a round, the American and National League series are pooled.
- The postseason row is the sum of its rounds. It is computed by folding them together, so it can never disagree with the rows beneath it.