--- a/web/app/models/compare_query.rb	Thu Oct 30 14:22:32 2014 +0100
+++ b/web/app/models/compare_query.rb	Thu Oct 30 14:23:44 2014 +0100
@@ -10,12 +10,11 @@
   end
 
   def filtered_benchmark_infos
-    BenchmarkInfo.where(id: benchmark_infos_to_array_of_ids)
+    BenchmarkInfo.where(id: filtered_benchmark_info_ids)
   end
 
-  private
+  def filtered_benchmark_info_ids
+    benchmark_infos.compact
+  end
 
-  def benchmark_infos_to_array_of_ids
-    benchmark_infos.keys
-  end
 end