Yelp More Likely to Filter Extreme Reviews and New AccountsAugust 8, 2013
Based on a study of 316,000 Yelp reviews, Michael Luca and Georgios Zervas have found that Yelp’s review filter had hidden more than 50,000 of those, or about 16% of the reviews that they scraped from the study.
And those filtered reviews shared some common characteristics tied both to the review itself, and to the person/account that wrote the review.
The study concluded that 1 and 5 star reviews are filtered more often than others. They also concluded that new accounts and the length of the review play a factor as well.
You can read more about the study here.