The task of assigning Game of the Year Awards for any source is a little more complicated than it probably should be.
The biggest question many gamers ask is- "Why can't we just go by the review scores? Obviously, the highest one for any particular source should get Game of the Year." Well, that's not necessarily true.
For some of the bigger sources with many critics on staff, the end-of-year awards are a result of a collaboration. Hence, if the one person who, for example, gave Grand Theft Auto V an 8.5 was outvoted by all the others who claim it's indeed the top game of 2013, GTAV wins. Something similar obviously happened at GameSpot, where they just gave PlayStation 3 GotY 2013 to the stellar PS3 exclusive, The Last Of Us . The game only scored an 8 when it was reviewed there, and it was up against multiple 9-scoring titles.
One could argue that most of those other games were multiplatform, and one should give GotY for a particular platform to an exclusive production. But Ni no Kuni: Wrath of the White Witch is a PS3 exclusive, and that scored a 9. So did Guacamelee (exclusive to PS3 and Vita). So, what happened? Like I said, the rest of the staff must've stepped up and outvoted the original critic for TLoU. But shouldn't readers consider the review to be a product of the site and not of the individual? Granted, only the individual reviewed it, but it's published under the brand name of the website. Hence, giving a game an 8 and then calling it GotY for that platform seems illogical.
Then there's another problem- When a game comes out, it can only be compared against other existing titles. Obviously, when scoring Bioshock Infinite , there was no way to know what TLoU or GTAV would be like. So, doesn't this mean that games scored at the end of the year should be given more weight? After all, they were pitted against most all big titles from the year, while those great games in February and March didn't have much in the way of competition. Really, it's a lot more complicated than you think…