diff --git a/app/models/value_group.rb b/app/models/value_group.rb
index 147f7cac979..275884b9b56 100644
--- a/app/models/value_group.rb
+++ b/app/models/value_group.rb
@@ -30,9 +30,11 @@ def series
         end
       end
 
+      first_child = children.first
+
       summed_series = summed_by_date.map { |date, value| { date: date, value: value } }
 
-      TimeSeries.new(summed_series)
+      TimeSeries.new(summed_series, favorable_direction: first_child&.series&.favorable_direction || "up")
     end
 
     def series=(series)