diff --git a/app/models/reviewable_score.rb b/app/models/reviewable_score.rb
index 208ea5b8fc5..34080a944d9 100644
--- a/app/models/reviewable_score.rb
+++ b/app/models/reviewable_score.rb
@@ -49,7 +49,7 @@ class ReviewableScore < ActiveRecord::Base
   # Generate `pending?`, `rejected?`, etc helper methods
   statuses.each do |name, id|
     define_method("#{name}?") { status == id }
-    self.class.define_method(name) { where(status: id) }
+    singleton_class.define_method(name) { where(status: id) }
   end
 
   def score_type