How does the rating system work?

I completely don't understand how the rating system on instructables works. When I click 5 stars on an instructable that has never been rated, it rates it 3.09. How does this work?

sort by: active | newest | oldest
kelseymh7 years ago
Type "Instructables Rating System" into the search box. One of the first hits should be Rachel's forum topic with all of the details. You can narrow the search by putting that phrase in quote, and also using "inurl:community" to limit the result to forum topics.
Interesting, I didn't realize that there were different weights based on whether the rater had commented or not.
Always has been to be 3.09 (for 5 stars) for me, how about every one else?
kelseymh7 years ago
For your specific question, the reported rating is an average between your individual "vote" and the set of all ratings of all kinds on the site. With only a small number of votes, the reported value will be close to the site-wide average (so that a few bad apples can't artificially skew things). As the number of new votes increases, the weight of the site-wide value will decrease and the result will asymptotically approach just the average of the votes.
kcls (author)  kelseymh7 years ago
So basically, the more I rate, the higher my rating gets? For example, a new person signs up for the site and rates something 5 stars and it goes to 3.09. Kiteman or you rate something 5 stars and it gets rated 4.5 stars? Is that how it works?
kelseymh kcls7 years ago
I don't believe that the weighting system has actually been deployed. You say that if you rate something 5 stars (as the first rating), it goes to 3.09. If I do the same thing (e.g., on this post :-), I get the same result.