Wednesday, June 20, 2012

Euro 2012 Tournament Odds

The European Championship pits the best 16* international soccer teams on the continent against each other, producing better matchups than the World Cup and fun Eurozone debt crisis proxy fights. The 16 teams are divided into four groups of four. Each group plays a round robin, with the top two in each group advancing to a single-elimination tournament.

* - Okay, 14 best teams and 2 host teams. But even the host nations are pretty good: There's no North Korea losing games 7-0.

The group stage just finished, and the tournament is about to get underway. Of the eight teams remaining, who has the best chance of winning it all?

For baseball and basketball games, you can calculate the expected win probability for a single game from the two teams' Pythagorean records using the log5 method. For international soccer, you can use the Elo ratings to determine the expected win probabilities. The formula looks like this:
We = 1 / (10(-dr/400) + 1),
where dr is the difference in Elo rankings between the two teams.

Once you know the probability that a team wins its first game, you can compute the probability that team wins its second game using conditional probabilities. Like this:
P(wins first game)*(P(beats potential opponent A)*P(potential opponent A wins first game)+P(beats potential opponent B)*P(potential opponent B wins first game))

Keep doing that and you eventually get win probabilities for the entire tournament:
Elo Semis Finals Champs Odds (x-to-1)
Spain 2110 83% 67% 44% 2.3
Germany 2063 85% 59% 32% 3.1
England 1950 61% 25% 10% 10.1
Portugal 1883 65% 18% 6.1% 16.4
Italy 1871 39% 12% 3.7% 27
France 1839 17% 9% 2.5% 40
Czech Rep. 1779 35% 6% 1.5% 68.3
Greece 1763 15% 4% 0.9% 112

And you're never going to believe this, but the teams with the best ratings are the ones with the highest chances to win. You can see that the probabilities depend a bit on matchups: France has only a 17% chance of knocking off Spain in the first round, but a 2.5% chance of winning the championship, whereas the Czech Republic has a 35% chance of beating Portugal but a 1.5% chance of making the finals, since they'd have a lower win probability against the remaining teams if they did advance.

Comparing the odds to the betting markets, it looks like Spain might actually be a good wager: if you believe this method, their odds to win are 2.3-to-1, but the books have them listed at 2.6-to-1. Practically everyone else is overvalued, but laughably so for Portugal (listed at 7.5-to-1), Italy (9-to-1), and France (12).

UPDATE #1: June 21, 4:45 p.m.
Here's what the odds look like after Portugal's win over the Czech Republic:
Elo Semis Finals Champs Odds (x-to-1)
Spain 2110 83% 64% 41% 2.4
Germany 2063 85% 59% 32% 3.1
Portugal 1901 100% 29% 11% 9.3
England 1950 61% 25% 10% 10.3
Italy 1871 39% 12% 3.6% 27.3
France 1839 17% 7% 2.1% 47.6
Greece 1763 15% 4% 0.9% 117
Note that everyone else's odds change, despite not playing, because of the improvement in Portugal's ranking. Portugal now has an 11% chance of winning the tournament, leapfrogging England, who obviously still has to survive the semifinal matchup. France, a bad bet to begin with, becomes a slightly worse bet now that they have to beat both Iberian Peninsula teams to get to the finals.

UPDATE #2: June 22, 4:45 p.m.
Here's what the odds look like after Germany's demolishing of the Greeks:
Elo Semis Finals Champs Odds (x-to-1)
Germany 2074 100% 70% 39% 2.6
Spain 2110 83% 64% 39% 2.6
Portugal 1901 100% 29% 9.6% 10.5
England 1956 62% 21% 8.4% 11.9
Italy 1871 38% 9% 2.7% 36.9
France 1839 17% 7% 1.8% 54.8
Germany are* technically the favorites by half a percentage point over Spain. But, again, Spain still has a first round match to play; with their odds somewhere in the 11-to-4 range (2.75-to-1), they still look like the best bet.

* - This always looks wrong to me, but everyone else does it. My least favorite thing about soccer.

UPDATE #3: June 25, 9:15 a.m.
Here's what the odds look like after this weekend's games, including the first upset of the knockout stages as the favored England side screwed up some penalty kicks to lose to Italy in a shootout:
Elo Semis Finals Champs Odds (x-to-1)
Spain 2123 100% 78% 49% 2.0
Germany 2074 100% 73% 36% 2.8
Italy 1902 100% 27% 7.6% 13.2
Portugal 1901 100% 22% 7.2% 13.8

This is the last update here, but I'll still post updates on Twitter. Italy's odds are slightly better than Portugal's, just because Germany has a lower rating than Spain's. I do like the fact that every German game from here out (vs. Italy, then vs. Spain/Portugal winner) is another Bailout Bowl, though some of that has to do with the woeful state of the Eurozone.

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