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Posted to solr-user@lucene.apache.org by Zac Smith <za...@trinkit.com> on 2012/03/12 19:38:12 UTC

Sort by bayesian function for 5 star rating

Does anyone have an example formula that can be used to sort by a 5 star rating in SOLR?
I am looking at an example on IMDB's top 250 movie list: 

The formula for calculating the Top Rated 250 Titles gives a true Bayesian estimate:
 weighted rating (WR) = (v ÷ (v+m)) × R + (m ÷ (v+m)) × C 
where:
    R = average for the movie (mean) = (Rating)
    v = number of votes for the movie = (votes)
    m = minimum votes required to be listed in the Top 250 (currently 3000)
    C = the mean vote across the whole report (currently 6.9)

Re: Sort by bayesian function for 5 star rating

Posted by Mike Austin <mi...@juggle.com>.

Why don't you just use that formula and calculate the weighted rating for
each movie and index that value? sort=wrating desc

Maybe I didn't understand your question.

mike

On Mon, Mar 12, 2012 at 1:38 PM, Zac Smith <za...@trinkit.com> wrote:

> Does anyone have an example formula that can be used to sort by a 5 star
> rating in SOLR?
> I am looking at an example on IMDB's top 250 movie list:
>
> The formula for calculating the Top Rated 250 Titles gives a true Bayesian
> estimate:
>  weighted rating (WR) = (v ÷ (v+m)) × R + (m ÷ (v+m)) × C
> where:
>    R = average for the movie (mean) = (Rating)
>    v = number of votes for the movie = (votes)
>    m = minimum votes required to be listed in the Top 250 (currently 3000)
>    C = the mean vote across the whole report (currently 6.9)
>
>