The baseball season is coming to a close, and with several clusters of closely matched teams, "tiebreaker" rules are coming into consideration, especially for three teams with identical records playing for the second wild card spot.

In that case, the three teams will be designated A, B, and C, with A and B playing at A's home field, and C playing the winner in the winner's home field.

The choices are made by the teams, with the teams getting choices in (descending) order of their head-to-head record.

The "natural" choice is C (only one game to play). I can't see anyone choosing B (worst of both worlds).

But might some teams choose A (two home games to qualify) over C (one road game)? Perhaps someone with a large home media market like the New York Yankees or Mets? (Neither are candidates this year.) Or perhaps a team that plays WAY better at home than on the road?


No, in fact you're likely a distinct disadvantage, but game theory comes into play here.

When teams A and B play, they are almost certainly going to each pitch their best starter in the game. If A wins, they are pitching their #2 starter vs C's #1.

Because home field advantage in baseball isn't a strong indicator of success Home teams only win about 54% of their games (same in postseason and regular season) at home. However, usually teams match up their best starters against each other in a playoff series.

So the first game favors team A by about 4%. Team C is going to have an advantage in the second game, even though they are the away team, because their #1 gets to go against the #2 of the team that won. Depending on the quality of team A's #2 starter, this may give team B enough of an edge to at least turn the game into a coinflip affair.

However, there is an additional consideration here. It's all about how much time passes between the tiebreaker game and the start of the first playoff series (or the wild card game). Team C might look at the matchup, and run out their #2 having confidence that he can beat the other team's #2 and save their rotation from getting out of whack in the first playoff series. This is a game theory decision and should be informed by way more math than I can pack into this little post (at least without running on for several pages and doing a lot more research that's not directly relevant here). If this happens, and we assume that #2 starters are equivalent, we're back to that 54% edge for the home team.

So, depending on how much of an impact you believe starting pitchers have on the outcome of a game (I tend to think it's a fair amount), the tie breaker situation either favors team C, but not by very much, or team A, but again, not by very much.

The reality is that playoff baseball is a crapshoot.


Assuming games are purely random chance, and assuming there aren't major external factors such as the second team having a single ace starter that there is a huge advantage to avoiding, C is favored.

Chance of winning, assuming home team is 54% road team 46%:

A: .54*.54 = .29 B: .46*.54 = .25 C: .46 = .46

A and B are splitting almost-evenly the chances of the home team winning, while C gets the whole road chance. A much better odds indeed.

As such, I'd always choose C, unless I were facing a team like the White Sox or the Indians, who have a single starter who is so far above the other starters on the team as to justify avoiding playing that starter. Even then, their #2 (Quintana and Carrasco) aren't exactly rubes.

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