2015 Norway Chess Tournament - Round 4

Shockingly, Carlsen loses again. Anand got his revenge in a well-played game. The model still thinks that Carlsen has some very remote chances of tying for first, in spite of his 0.5/4 start. Topalov is the favorite now; he leads with 3.5/4 and faces the bottom seed (Hammer) in the next round.

Methodology

I certainly did not predict that Carlsen would be so sensationally unsuccessful in the first 4 rounds. The natural question is, how unlikely is his performance? According to the model, there is a 1.9% chance of him starting with 0.0/2 against Topalov and Caruana. This is roughly equal to the probability of tossing a coin and getting heads 6 times in a row. We can also ask, what is the probability that he scores no more than 0.5/4 against Topalov, Anand, Giri, and Caruana? The answer is about 0.6% - slightly less likely than tossing a coin and getting heads 7 times in a row, slightly more likely than rolling 3 dice and getting all 6's.