I am looking at the Anand vs Andreikin round 12 Candidates tournament and I see that it ended in a draw and that based on engine evaluation Anand is much better (+ 2.8 is kind of huge). I also see that it is really a hard position and to be able to get advantage it requires you to sacrifice a rook basically for nothing (you will not get anything back in next moves). Anand proceeded with repetition thus drawing the game.
I know that the question is highly speculative and no one knows the answer except of Anand. But has he not seen that he is better, may be he was low on time, or something else? (I definitely has not seen it, and even from my first 3 minutes of analysis it looks like he is worse, but this is why I am not a GM :-) ).
A more appropriate question will be about normal analysis of the position.
Here is the mentioned game:
[White "Anand"] [Black "Andreikin"] [Event "Candidates tournament 2014 ( round 12 )"] [fen ""] 1.e4 c6 2.d4 d5 3.Nc3 dxe4 4.Nxe4 Bf5 5.Ng3 Bg6 6.h4 h6 7.Nf3 e6 8.Ne5 Bh7 9.Bd3 Bxd3 10.Qxd3 Nd7 11.f4 Bb4+ 12.c3 Be7 13.Bd2 Ngf6 14.O-O-O O-O 15.Qf3 Qc7 16.c4 a5 17.Kb1 Rad8 18.Bc1 a4 19.Rhe1 a3 20.b3 Bb4 21.Re3 c5 22.d5 exd5 23.cxd5 Nb6 24.Red3 Qc8 25.d6 Rfe8 26.Nh5 Re6 27.Nxf6 Rxf6 28.d7 Qc7 29.Qg4 c4 30.Rg3 g6 31.h5 cxb3 32.Rxb3 Na4 33.hxg6 fxg6 34.Rxb4 Nc3+ 35.Kc2 b5 36.Kb3 Na4 37.Qf3 Nc5+ 38.Kc2 Na4+ 39.Kb3 Nc5+ 40.Kc2 Na4+ 41.Kb3 1/2-1/2