diff --git a/lib/assessor.rb b/lib/assessor.rb
index 1d395dc7..ac0f5d42 100644
--- a/lib/assessor.rb
+++ b/lib/assessor.rb
@@ -5,7 +5,7 @@ class Assessor
     test_outcome = @testing_framework_adapter.test_outcome(output)
     test_outcome.merge(score: calculate_score(test_outcome))
   rescue
-    {score: 0}
+    {score: 0.0}
   end
 
   def calculate_score(test_outcome)
diff --git a/spec/models/submission_spec.rb b/spec/models/submission_spec.rb
index e01887fe..b97d5b88 100644
--- a/spec/models/submission_spec.rb
+++ b/spec/models/submission_spec.rb
@@ -53,7 +53,7 @@ describe Submission do
     context 'without a score' do
       before(:each) { submission.score = nil }
 
-      it 'returns nil' do
+      it 'returns 0' do
         expect(submission.normalized_score).to be 0
       end
     end
@@ -72,7 +72,7 @@ describe Submission do
     context 'without a score' do
       before(:each) { submission.score = nil }
 
-      it 'returns nil' do
+      it 'returns 0' do
         expect(submission.percentage).to be 0
       end
     end