diff --git a/app/services/survey_response_aggregator.rb b/app/services/survey_response_aggregator.rb
index c31c2816..c7e8a016 100644
--- a/app/services/survey_response_aggregator.rb
+++ b/app/services/survey_response_aggregator.rb
@@ -1,9 +1,3 @@
-class Array
-  def average
-    self.sum.to_f / self.size
-  end
-end
-
 class SurveyResponseAggregator
   def self.score(academic_year:, school:, measure:)
     SurveyItemResponse
diff --git a/config/initializers/array_monkey_patches.rb b/config/initializers/array_monkey_patches.rb
new file mode 100644
index 00000000..a160670b
--- /dev/null
+++ b/config/initializers/array_monkey_patches.rb
@@ -0,0 +1,7 @@
+module ArrayMonkeyPatches
+  def average
+    self.sum.to_f / self.size
+  end
+end
+
+Array.include ArrayMonkeyPatches