The only bias from Gamerankings and Metacritic comes from the source of the reviews despite basing scores on an average index of those sources. That's probably the biggest shortcoming of both sites, and certainly the greatest flaw in using either as the so-called proof of objective ratings.
If either site had a cream of the crop ratings from the most respected publications and review sources, that would be a fairly different situation. But seeing as how self promoted high school grade blogger sites are thrown into the review index averages as well as many equally unreliable and excessively biased "official" review sources, it's pretty hard to take either without a boulder of salt.







