Ecosyste.ms: Awesome

An open API service indexing awesome lists of open source software.

Awesome Lists | Featured Topics | Projects

https://github.com/tyrauber/acts_rateable

Rails 3 Bayesian Ratings Gem
https://github.com/tyrauber/acts_rateable

Last synced: 3 months ago
JSON representation

Rails 3 Bayesian Ratings Gem

Awesome Lists containing this project

README 

        
# ActsRateable



ActsRateable is a Rails 3 ruby gem designed to enable bi-directional polymorphic rating - users rate companies, companies rate users.  It records individual rates and caches ratings, enable quick ordering of resources by rating.



The cached ratings contain four different points of data:



		:total  => rate count

		:average => rate average

		:sum => rate sum

		:estimate => rate estimate



The estimate is probably the most useful of the data points, as it provides a weighted score based on the number of times the resource has been rated.



To determine this estimate, the gem calculates a bayesian estimate, as inspired by IMDB's top 250 list.



## Inspiration



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

  C = the mean vote across the whole report (currently 7.1)



## Implementation



	* R = average rating for resource

	* v = number of ratings for resource

	* m = average number of votes

	* C = average rating of all resources



## Installation



1) Include the gem in your rails project gem file.



		gem 'acts_rateable'



2) Run:



		bundle install

		rails generate acts_rateable

		rake db:migrate



3) Add `acts_rateable` to the models you wish to have the ability to rate or be rated.



## Usage



### author.rate( resource, value )



To rate a resource:



		author.rate( resource, value )



For example,



		current_user.rate( post, 5 )



### resource.rated_by?( author )



To test whether a resource has been rated an author:



		post.rated_by?( author )



The rate will be returned if the user has rated the resource, otherwise an empty set of ratings is returned.



You may want to test it like this to get a true/false:



    post.rated_by?( author ).empty?



### author.has_rated?( resource )



To test whether an author has rated a resource:



		current_user.has_rated?( post )



The rate will be returned in the user has rated the resource, otherwise false will be returned.



### resource.rating



To get the rating for a resource:



		post.rating



### resource.rating[column]



Four types of data are cached for every resource rated:



		:total  => rate count

		:average => rate average

		:sum => rate sum

		:estimate => rate estimate



For example:



		post.rating( :total )



Will return the rate count.



		post.rating( :average )



Will return the rate average.



		post.rating( :sum )



Will return the rate sum.



		post.rating( :estimate )



Will return the rate estimate.



### resource.variation(author)



To find out how close or far off the author was in their rating from the resource estimate:



		post.variation(author)



Will return a percentage of deviation.



### order_by_rating(column, direction)



Any rateable resource may be ordered by any of the four cached data points, in either direction: DESC, ASC.



For example:



	Post.order_by_rating(:estimate, 'DESC')



Will return all posts ordered by estimate in descending order.



## Support



For issues, problems or bugs, please post an issue, here:



  https://github.com/tyrauber/acts_rateable/issues



## Future Development



For future development:



  1) fork the repository

  2) extend the functionality

  3) issue pull request