diff --git a/app/models/choice.rb b/app/models/choice.rb
index ef39331..ce96cf2 100644
--- a/app/models/choice.rb
+++ b/app/models/choice.rb
@@ -82,6 +82,26 @@ class Choice < ActiveRecord::Base
     self.item.creator_id != self.question.creator_id
   end
 
+  def compute_bt_score(btprobs = nil)
+      if btprobs.nil?
+	      btprobs = self.question.bradley_terry_probs
+      end
+
+      p_i = btprobs[self.id]
+
+      total = 0
+      btprobs.each do |id, p_j|
+	      if id == self.id
+		      next
+	      end
+
+	      total += (p_i / (p_i + p_j))
+      end
+
+      total / (btprobs.size-1)
+
+  end
+
   
   protected
 
diff --git a/app/models/question.rb b/app/models/question.rb
index b77df03..7087b9e 100644
--- a/app/models/question.rb
+++ b/app/models/question.rb
@@ -93,6 +93,73 @@ class Question < ActiveRecord::Base
 	   weighted.each_with_index {|item, i| weighted[i] = item/sum}
    end
   end
+
+ def bradley_terry_probs
+   probs = []
+   prev_probs = []
+
+   # What ordering key we use is unimportant, just need a consistent way to link index of prob to id
+   the_choices = self.choices.sort{|x,y| x.id<=>y.id}
+
+   # This hash is keyed by pairs of choices - 'LC.id, RC.id'
+   the_prompts = prompts_hash_by_choice_ids
+
+   # Initial probabilities chosen at random
+   the_choices.size.times do 
+	   probs << rand
+	   prev_probs << rand
+   end
+
+   t=0
+   probs_size = probs.size
+   
+   # probably want to add a fuzz here to account for floating rounding
+   until probs == prev_probs do
+      s = t % probs_size
+      prev_probs = probs.dup
+      choice = the_choices[s]
+
+      numerator = choice.wins.to_f
+
+      denominator = 0.0
+      the_choices.each_with_index do |c, index|
+	      if(index == s)
+		      next
+	      end
+
+	      wins_and_losses = the_prompts["#{choice.id}, #{c.id}"].votes.size + the_prompts["#{c.id}, #{choice.id}"].votes.size
+	      denominator+= (wins_and_losses).to_f / (prev_probs[s] + prev_probs[index])
+      end
+      probs[s] = numerator / denominator 
+      normalize!(probs)
+      t+=1
+   end
+ 
+   probs_hash = {}
+   probs.each_with_index do |item, index| 
+	   probs_hash[the_choices[index].id] = item
+   end
+   probs_hash
+ end
+
+ 
+ def all_bt_scores
+	 btprobs = bradley_terry_probs
+	 btprobs.each do |key, value|
+		 c = Choice.find(key)
+		 puts "#{c.id}: #{c.votes.size} #{c.compute_bt_score(btprobs)}"
+	 end
+
+ end
+
+ def prompts_hash_by_choice_ids
+   the_prompts = {}
+   self.prompts.each do |p|
+      the_prompts["#{p.left_choice_id}, #{p.right_choice_id}"] = p
+   end
+   the_prompts
+ end
+
    
    def distinct_array_of_choice_ids(rank = 2, only_active = true)
      @choice_ids = choice_ids
diff --git a/lib/tasks/import_bt_test_data.rb b/lib/tasks/import_bt_test_data.rb
new file mode 100644
index 0000000..7775f54
--- /dev/null
+++ b/lib/tasks/import_bt_test_data.rb
@@ -0,0 +1,62 @@
+require 'faster_csv'
+
+BASEDIR = "/home/dhruv/CITP/bt_test/"
+
+q = Question.new(:name => "test for bt", :creator_id => 1, :site_id => 1)
+q.save()
+
+choice_offset = Choice.last.id
+
+inserts = []
+
+timestring = Time.now.to_s(:db) #isn't rails awesome?
+totalchoices=0
+FasterCSV.foreach(BASEDIR + "choices_7000.txt", {:headers => :first_row, :return_headers => false}) do |choice|
+# for each choice, create an insert with unique id
+   id = choice[0].to_i + choice_offset
+   wins = choice[1].to_i
+   inserts.push("(#{q.id}, #{id}, #{wins}, '#{timestring}', '#{timestring}')")
+   totalchoices+=1
+end
+
+sql = "INSERT INTO `choices` (`question_id`, `item_id`, `votes_count`, `created_at`, `updated_at`) VALUES #{inserts.join(', ')}"
+
+ActiveRecord::Base.connection.execute(sql)
+
+inserts = []
+prompt_offset = Prompt.last.id
+totalprompts = 0
+FasterCSV.foreach(BASEDIR + "prompts_7000.txt", {:headers => :first_row, :return_headers => false}) do |prompt|
+   id = prompt[0].to_i + prompt_offset
+   left_choice_id = prompt[1].to_i + choice_offset
+   right_choice_id = prompt[2].to_i + choice_offset
+   votes_count =  prompt[3].to_i
+
+   inserts.push("(NULL, #{q.id}, NULL, #{left_choice_id}, '#{timestring}', '#{timestring}', NULL, #{votes_count}, #{right_choice_id}, NULL, NULL)")
+   totalprompts +=1
+end
+
+sql = "INSERT INTO `prompts` (`algorithm_id`, `question_id`, `voter_id`, `left_choice_id`, `created_at`, `updated_at`, `tracking`, `votes_count`, `right_choice_id`, `active`, `randomkey`) VALUES #{inserts.join(', ')}"
+
+ActiveRecord::Base.connection.execute(sql)
+
+inserts = []
+vote_offset = Vote.last.id
+totalvotes=0
+FasterCSV.foreach(BASEDIR + "votes_7000.txt", {:headers => :first_row, :return_headers => false}) do |vote|
+   id = vote[0].to_i + vote_offset
+   prompt_id = vote[1].to_i + prompt_offset 
+   choice_id = vote[2].to_i + choice_offset
+   loser_choice_id = vote[3].to_i 
+
+   inserts.push("(#{prompt_id}, #{q.id}, #{choice_id}, #{loser_choice_id}, '#{timestring}', '#{timestring}')")
+   totalvotes +=1
+end
+
+sql = "INSERT INTO `votes` (`prompt_id`, `question_id`, `choice_id`, `loser_choice_id`, `created_at`, `updated_at`) VALUES #{inserts.join(', ')}"
+
+ActiveRecord::Base.connection.execute(sql)
+
+sql = "UPDATE questions SET votes_count=#{totalvotes}, prompts_count=#{totalprompts}, choices_count=#{totalchoices} WHERE id=#{q.id}"
+
+ActiveRecord::Base.connection.execute(sql)
diff --git a/lib/tasks/makecsvfromhash.rb b/lib/tasks/makecsvfromhash.rb
new file mode 100644
index 0000000..334fef3
--- /dev/null
+++ b/lib/tasks/makecsvfromhash.rb
@@ -0,0 +1,25 @@
+require 'fastercsv'
+
+q = Question.find(109)
+
+the_prompts = q.prompts_hash_by_choice_ids
+
+#hash_of_choice_ids_from_left_to_right_to_votes
+the_hash = {}
+the_prompts.each do |key, p|
+	left_id, right_id = key.split(", ")
+        if not the_hash.has_key?(left_id)
+	   the_hash[left_id] = {}
+	   the_hash[left_id][left_id] = 0
+	end
+
+        the_hash[left_id][right_id] = p.votes.size
+end
+
+the_hash.sort.each do |xval, row|
+	rowarray = []
+	row.sort.each do |yval, cell|
+		rowarray << cell
+	end
+	puts rowarray.join(", ")
+end
--
libgit2 0.21.2