diff --git a/app/models/conversational_development_index/idea_to_production_step.rb b/app/models/conversational_development_index/idea_to_production_step.rb
index f53227f8a27..6e1753c9f30 100644
--- a/app/models/conversational_development_index/idea_to_production_step.rb
+++ b/app/models/conversational_development_index/idea_to_production_step.rb
@@ -9,9 +9,9 @@ module ConversationalDevelopmentIndex
     end
 
     def percentage_score
-      sum = features.map do |feature|
+      sum = features.sum do |feature|
         metric.percentage_score(feature)
-      end.inject(:+)
+      end
 
       sum / features.size.to_f
     end
diff --git a/app/presenters/conversational_development_index/metric_presenter.rb b/app/presenters/conversational_development_index/metric_presenter.rb
index 220014a955a..bb65ba2646b 100644
--- a/app/presenters/conversational_development_index/metric_presenter.rb
+++ b/app/presenters/conversational_development_index/metric_presenter.rb
@@ -138,7 +138,7 @@ module ConversationalDevelopmentIndex
     end
 
     def average_percentage_score
-      cards.map(&:percentage_score).inject(:+) / cards.size.to_f
+      cards.sum(&:percentage_score) / cards.size.to_f
     end
   end
 end