Replace integer devision with float division for accurate response rate calculation

app/models/response_rate.rb

@@ -6,7 +6,6 @@ class ResponseRate
   end
 
   def student
-    @student_response_rate ||= begin
     return 0 unless student_survey_item_count.positive?
 
     average_responses_per_survey_item = student_response_count / student_survey_item_count
@@ -15,10 +14,8 @@ class ResponseRate
 
     (average_responses_per_survey_item / total_possible_student_responses * 100).round
   end
-  end
 
   def teacher
-    @teacher_response_rate ||= begin
     return 0 unless teacher_survey_item_count.positive?
 
     average_responses_per_survey_item = teacher_response_count / teacher_survey_item_count
@@ -27,7 +24,6 @@ class ResponseRate
 
     (average_responses_per_survey_item / total_possible_teacher_responses * 100).round
   end
-  end
 
   private
 
@@ -51,38 +47,24 @@ class ResponseRate
   end
 
   def student_response_count
-    @student_response_count ||= response_count do |measure|
-      next 0 unless measure.includes_student_survey_items?
-
-      SurveyItemResponse.student_responses_for_measure(measure, @school, @academic_year).count
-    end
+    @student_response_count ||= SurveyItemResponse.student_responses_for_measures(@subcategory.measures, @school,
+                                                                                 @academic_year).count.to_f
   end
 
   def teacher_response_count
-    @teacher_response_count ||= response_count do |measure|
-      next 0 unless measure.includes_teacher_survey_items?
-
-      SurveyItemResponse.teacher_responses_for_measure(measure, @school, @academic_year).count
-    end
-  end
-
-  def response_count(&block)
-    @subcategory.measures.map(&block).sum
+    @teacher_response_count ||= SurveyItemResponse.teacher_responses_for_measures(@subcategory.measures, @school,
+                                                                                 @academic_year).count.to_f
   end
 
   def student_survey_item_count
-    @student_survey_item_count ||= survey_item_count do |measure|
+    @student_survey_item_count ||= @subcategory.measures.map do |measure|
       measure.student_survey_items.count
-    end
+    end.sum.to_f
   end
 
   def teacher_survey_item_count
-    @teacher_survey_item_count ||= survey_item_count do |measure|
+    @teacher_survey_item_count ||= @subcategory.measures.map do |measure|
       measure.teacher_survey_items.count
-    end
-  end
-
-  def survey_item_count(&block)
-    @subcategory.measures.map(&block).sum
+    end.sum.to_f
   end
 end

app/models/survey_item_response.rb

@@ -68,11 +68,19 @@ class SurveyItemResponse < ActiveRecord::Base
                                           for_measure(measure, school, academic_year)
                                             .where("survey_items.survey_item_id LIKE 't-%'")
                                         }
+  scope :teacher_responses_for_measures, lambda { |measures, school, academic_year|
+                                           for_measures(measures, school, academic_year)
+                                             .where("survey_items.survey_item_id LIKE 't-%'")
+                                         }
   scope :student_responses_for_measure, lambda { |measure, school, academic_year|
                                           for_measure(measure, school, academic_year)
                                             .where("survey_items.survey_item_id LIKE 's-%'")
                                         }
 
+  scope :student_responses_for_measures, lambda { |measures, school, academic_year|
+                                           for_measures(measures, school, academic_year)
+                                             .where("survey_items.survey_item_id LIKE 's-%'")
+                                         }
   def self.student_sufficient_data?(measure:, school:, academic_year:)
     if measure.includes_student_survey_items?
       student_survey_item_responses = SurveyItemResponse.student_responses_for_measure(measure, school, academic_year)

spec/models/response_rate_spec.rb

@@ -48,6 +48,7 @@ describe ResponseRate, type: :model do
     let(:insufficient_measure) { create(:measure, subcategory: subcategory) }
     let(:sufficient_teacher_survey_item_1) { create(:teacher_survey_item, measure: sufficient_measure_1) }
     let(:sufficient_teacher_survey_item_2) { create(:teacher_survey_item, measure: sufficient_measure_1) }
+    let(:sufficient_teacher_survey_item_3) { create(:teacher_survey_item, measure: sufficient_measure_1) }
     let(:sufficient_student_survey_item_1) { create(:student_survey_item, measure: sufficient_measure_1) }
     let(:insufficient_teacher_survey_item) { create(:teacher_survey_item, measure: insufficient_measure) }
     let(:insufficient_student_survey_item) { create(:student_survey_item, measure: insufficient_measure) }
@@ -66,11 +67,21 @@ describe ResponseRate, type: :model do
                   survey_item: insufficient_student_survey_item, academic_year: ay, school: school, likert_score: 1)
     end
 
-    context 'when the average number of student responses per question in a subcategory is equal to the student response threshold' do
+    context 'when the average number of teacher responses per question in a subcategory is equal to the teacher response threshold' do
       it 'returns 100 percent' do
         expect(ResponseRate.new(subcategory: subcategory, school: school,
                                 academic_year: ay).teacher).to eq 100
       end
     end
+    context 'when the average number of teacher responses is 77.9, the response rate averages up to 78 percent' do
+      before do
+        create_list(:survey_item_response, 2, survey_item: sufficient_teacher_survey_item_3,
+                                                                                                academic_year: ay, school: school, likert_score: 1)
+      end
+      it 'returns 10 percent' do
+        expect(ResponseRate.new(subcategory: subcategory, school: school,
+                                academic_year: ay).teacher).to eq 78
+      end
+    end
   end
 end