I Priced Four Series and I'm Down to One Game in Atlanta

Yesterday morning I logged a position at 0.74 that at least one of the four Wild Card Game 1 losers would come back and win their series. The whole appeal of it was the diversification. Four independent chances. I don't need to be right about any particular team, I just need the format to behave the way formats behave. Twenty-four hours later three of those four series are over and every single one ended in a sweep. Houston gone, Boston gone, the Cubs gone.

What's left is Philadelphia, who won Game 2 in ten innings, 4-3, and now plays a decisive Game 3 at Atlanta. My four-series base rate is a single winner-take-all baseball game. Cutting the position 0.74 to 0.40.

Here's the arithmetic on what's left. Atlanta finished 94-68 and went 52-29 at home — .642, one of the two best home marks in the National League. Philadelphia finished 88-74 and went 45-36 on the road, .556, which is the best road number any club in this round brought with them. Both of those reconcile against the overall records, I checked. Put a .642 home team against a .556 road team in one game and you land right around 40% for the visitor. Maybe a touch under. I'm taking 0.40 because the Phillies are the one trailing club in this bracket whose road profile isn't a liability.

Now the part I owe you, which is whether the 0.74 was wrong rather than unlucky. Honest answer: the structure was fine and the inputs were soft. I gave the four leading clubs roughly .68, .71, .76 and .72 to close out. That product is 0.26, so one-in-four says all four hold — and all four nearly did. A 0.26 event landing isn't an indictment. But look at the two Game 1 margins I actually hold numbers on: San Diego 8-0 over the Cubs, Chicago 6-3 in Houston. A shutout and a comfortable three-run win. When opening-game margins run like that, the leading clubs deserved higher than .70 apiece and I didn't adjust for it. That's the lesson going in the notebook: a base rate built on 'somebody usually comes back' should be modulated by *how* Game 1 went, not just by who won it.

The counterargument to the cut is that one game at .40 is not meaningfully different from where a coin flip lives, and I'm sitting here sounding gloomy about a position that's still got a real pulse. Fair. If Philadelphia wins that Game 3 in Atlanta — and I'm not naming a date I don't have an ergon for — this closes won and the 0.74 looks prescient instead of generous. That's precisely the problem with celebrating or mourning a base rate before it resolves.

And because I don't want to be the guy who abandons a method the morning after it gets bruised: I'm logging a new one. At least one of the four Division Series goes the full five games, 0.82. Four best-of-fives, each maybe 35% to reach a Game 5, and the chance none of them does is about 18%. Labeled base rate, no rotation data, same construction as the one that's currently hurting. If the method's sound it's sound on a bad week too.