diff --git a/app/models/question.rb b/app/models/question.rb
index b6b022a..c8cf524 100644
--- a/app/models/question.rb
+++ b/app/models/question.rb
@@ -276,19 +276,40 @@ class Question < ActiveRecord::Base
       nonseed_nonseed_sum= 0
       nonseed_nonseed_total= 0
 
+      #cache some hashes to prevent tons of sql thrashing
+      num_appearances_by_prompt = self.appearances.count(:group => :prompt_id)
+
+
+      is_user_created = {}
+      self.choices.each do |c|
+	      is_user_created[c.id] = c.user_created
+      end
+
+
       #the_prompts = prompts.find(:all, :include => ['left_choice', 'right_choice'])
-      prompts.find_each(:include => ['left_choice', 'right_choice']) do |p|
-	      if p.left_choice.user_created == false && p.right_choice.user_created == false
-		      seed_seed_sum += p.appearances.size
+      prompts.find_each do |p|
+
+	      num_appearances = num_appearances_by_prompt[p.id]
+
+	      if num_appearances.nil?
+		      num_appearances = 0
+	      end
+
+	      left_user_created = is_user_created[p.left_choice_id]
+	      right_user_created = is_user_created[p.right_choice_id]
+
+
+	      if left_user_created == false && right_user_created == false
+		      seed_seed_sum += num_appearances
 		      seed_seed_total +=1
-	      elsif p.left_choice.user_created == false && p.right_choice.user_created == true
-		      seed_nonseed_sum += p.appearances.size
+	      elsif left_user_created == false && right_user_created == true
+		      seed_nonseed_sum += num_appearances
 		      seed_nonseed_total +=1
-	      elsif p.left_choice.user_created == true && p.right_choice.user_created == false
-		      nonseed_seed_sum += p.appearances.size
+	      elsif left_user_created == true && right_user_created == false
+		      nonseed_seed_sum += num_appearances
 		      nonseed_seed_total +=1
-	      elsif p.left_choice.user_created == true && p.right_choice.user_created == true
-		      nonseed_nonseed_sum += p.appearances.size
+	      elsif left_user_created == true && right_user_created == true
+		      nonseed_nonseed_sum += num_appearances
 		      nonseed_nonseed_total +=1
 	      end
       end
diff --git a/lib/tasks/test_api.rake b/lib/tasks/test_api.rake
index 84db766..953b9f8 100644
--- a/lib/tasks/test_api.rake
+++ b/lib/tasks/test_api.rake
@@ -211,9 +211,33 @@ namespace :test_api do
 
    desc "Generate density information for each question - should be run nightly"
    task(:generate_density_information => :environment) do
-	   Question.find(:all).each do |q|
+
+	   # calculating densities is expensive, so only do it for questions with new data
+	   question_ids = Vote.count(:conditions => ['date(created_at) = ?', Date.yesterday], :group => 'question_id').keys()
+
+	   Question.find(:all, :conditions => {:id => question_ids}).each do |q|
 		   q.save_densities!
 	   end
+
+	   # we can just copy the previous night's data for remaining questions
+	   
+	   Question.find(:all, :conditions => ['id NOT IN (?)', question_ids]).each do |q|
+		   densities = q.densities.find(:all, :conditions => ['date(created_at) = ?', Date.yesterday])
+
+
+		   densities.each do |d|
+			   new_d = d.clone
+			   new_d.created_at = new_d.updated_at = Time.now
+			   new_d.save!
+		   end
+
+		   if densities.blank?
+			   #fallback in case there wasn't a successful run yesterday
+			   q.save_densities!
+			   
+		   end
+
+	   end
    end
       
    desc "Description here"
--
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