WeightedScore

Weighted Score provides a light weight framework for creating weighted scoring systems. It allows you to calculate weighted scores using score calculator classes for each of the weighted components.

Installation

Add this line to your application's Gemfile:

gem 'weighted_score'

And then execute:

$ bundle

Or install it yourself as:

$ gem install weighted_score

Usage

Start by creating one or more score calculating classes. You can optionally subclass WeightedScore::Score. If you do not subclass the provided Score class then you your initializer should accept one argument which represents the scorable item and you must implement a calculate method.

Either way the calculate method must return a numeric value.

require 'weighted_score'

class CriteriaOne < WeightedScore::Score
  def calculate
    return 1 if scorable >= 10
    0
  end
end

class CriteriaTwo < WeightedScore::Score
  def calculate
    return 1 if scorable.even?
    0
  end
end

class CriteriaThree < WeightedScore::Score
  def calculate
    return 1 if scorable % 4 == 0
    0
  end
end

Then create a weighted score calculator class:

require 'weighted_score'

class Calculator < WeightedScore::WeightedScore
  score CriteriaOne => 0.5
  score CriteriaTwo => 0.25
  score CriteriaThree => 0.25
end

Finally, you can then use it like this:

Calculator.new(5).calculate      #=> 0
Calculator.new(2).calculate      #=> 0.25
Calculator.new(4).calculate      #=> 0.5
Calculator.new(12).calculate     #=> 1
Calculator.new(13).calculate     #=> 0.5
Calculator.new(14).calculate     #=> 0.75

An Example Customer Valuation Calculator

require 'weighted_score'

class EmailScore < WeightedScore::Score
  def calculate
    return 1 if scorable.email.present?
    0
  end
end

class NewsletterScore < WeightedScore::Score
  def calculate
    return 1 if scorable.newsletter_status == 'subscribed'
    0
  end
end

class OrdersScore < WeightedScore::Score
  def calculate
    scorable.orders.size - scorable.returns.size
  end
end

class CustomerValuation < WeightedScore::WeightedScore
  score EmailScore => 5
  score NewsletterScore => 10
  score OrdersScore => 1
end

CustomerValuation.new(user).calculate

Contributing

Fork it ( https://github.com/Originate/weighted_score/fork )
Create your feature branch (git checkout -b my-new-feature)
Commit your changes (git commit -am 'Add some feature')
Push to the branch (git push origin my-new-feature)
Create a new Pull Request

weighted_score

Development

WeightedScore

Installation

Usage

An Example Customer Valuation Calculator

Contributing