scope school_categories to valid ones

app/controllers/categories_controller.rb

@@ -14,7 +14,7 @@ class CategoriesController < ApplicationController
     district = @school.district
     authenticate(district.name.downcase, "#{district.name.downcase}!")
     @school_category = SchoolCategory.for(@school, @category).first
-    @child_school_categories = SchoolCategory.for_parent_category(@school, @category)
+    @child_school_categories = SchoolCategory.for_parent_category(@school, @category).valid
     @questions = @category.questions
   end
 

app/models/school_category.rb

@@ -9,6 +9,8 @@ class SchoolCategory < ApplicationRecord
   scope :for, -> (school, category) { where(school: school).where(category: category) }
   scope :for_parent_category, -> (school, category=nil) { where(school: school).joins(:category).merge(Category.for_parent(category)) }
 
+  scope :valid, -> { where("answer_index_total > 0 or zscore is not null") }
+
   def answer_index_average
     answer_index_total.to_f / response_count.to_f
   end
@@ -32,8 +34,8 @@ class SchoolCategory < ApplicationRecord
     _aggregated_responses = aggregated_responses
 
     child_school_categories = category.child_categories.collect do |cc|
-      SchoolCategory.for(school, cc)
-    end.flatten
+      SchoolCategory.for(school, cc).valid
+    end.flatten.compact
 
     new_zscore = zscore
     if new_zscore.nil?

app/views/school_categories/_indicator.html.haml

@@ -6,6 +6,8 @@
   - likert = info.answer_index_average.nan? ? zscore : (info.answer_index_average + zscore) / 2
 - likert = likert.round(1)
 
+- return if likert.nan?
+
 - average_offset = (likert/num_likerts) * 100
 
 - approval_zone = [[76, 90], [77, 91], [71, 85], [73, 86], [73, 86], []][info.category.root_index]