diff --git a/app/models/question.rb b/app/models/question.rb
index 9d261ac..9406624 100644
--- a/app/models/question.rb
+++ b/app/models/question.rb
@@ -690,7 +690,7 @@ class Question < ActiveRecord::Base
         UNION ALL
         (SELECT skipper_id vid FROM skips WHERE question_id = #{id})
       ) b GROUP BY b.vid ORDER BY total
-    "), true) || 0
+    "), true) || nil
   end
 
   def upload_to_participation_ratio
diff --git a/spec/integration/questions_spec.rb b/spec/integration/questions_spec.rb
index 92a565c..17a00c1 100644
--- a/spec/integration/questions_spec.rb
+++ b/spec/integration/questions_spec.rb
@@ -285,6 +285,9 @@ describe "Questions" do
     before(:all) { truncate_all }
     it "should return the median responses per session" do
       q = Factory.create(:aoi_question, :site => @api_user)
+      get_auth median_responses_per_session_question_path(q, :format => 'xml')
+      response.should be_success
+      response.body.should have_tag("median[nil=true]", :text => "")
       Factory.create(:vote_new_user, :question => q)
       v = Factory.create(:vote_new_user, :question => q)
       Factory.create(:vote, :question => q, :voter => v.voter)
--
libgit2 0.21.2