Wikipedia
Metacritic is a website that aggregates reviews of music albums, games, movies, TV shows, DVDs, and formerly, books. For each product, a numerical score from each review is obtained and the total is averaged. It was created and founded by Jason Dietz, Marc Doyle, and Julie Doyle Roberts. An excerpt of each review is provided along with a hyperlink to the source. Three color codes of Green, Yellow and Red summarize the critic's recommendation, giving an idea of the general appeal of the product among reviewers and, to a lesser extent, the public. It is regarded as the video game industry's foremost review aggregator.
Metacritic's method of scoring converts each review into a percentage that the site decides for itself, before taking a weighted average based on the critic's fame or stature, and listing different numbers of reviews. Many review websites give a review grade out of five, out of ten, out of a hundred, or even an alphabetical score. Metacritic converts such a grade into a percentage. For reviews with no explicit scores (for example, The New York Times reviews), Metacritic manually assesses the tone of the review before assigning a relevant grade.