Google Drops Review Star Threshold to 1 or 2 Reviews AND Stops Using Bayesian Average
February 06, 2017
Last week we reported the fact that Google had lowered the threshold for showing review stars in the search results from 5 to 3 total reviews. Over the weekend, numerous reports came in from Europe, Australia and the US of the threshold to showing stars having dropped to 2. That appears to be the case world wide. There are also reports of even one review showing the stars on a business listing but it does not yet appear to be the case universally.
Review Averages Change As Well
Equally interesting to me is that Google is now using the arithmetic average that we all learned in grade school and is no longer using the Bayesian average to calculate the review score. A Bayesian average looks at the larger data set for all businesses to calculate the likelihood of the particular average for a given business being lower when they have few reviews.
The upshot of this change is that a business with a perfect 5 on their ratings with 2 to 10 reviews will now get a 5 star rating. Previously if a business had less than 10 reviews and a 5 Star arithmetic average Google would show a 4.8 or 4.9 rating for that business.
Using the Bayesian average may have been a more accurate statistical picture, but users and small business never liked it and complaints come up repeatedly in the forums. Consumers thought that businesses were cooking the books and the businesses thought that someone was messing with them.
Google’s use of a simple average that both consumers and businesses understand is a welcome change.