diff --git a/atlas/views.py b/atlas/views.py
index 59e97de7..8ebfc277 100755
--- a/atlas/views.py
+++ b/atlas/views.py
@@ -1085,7 +1085,7 @@ def collection_mark_overview(request, pk):
 
     answers = CidReportAnswer.objects.filter(question=case_details)
 
-    case_map = []
+    case_map = {}
     for cd in case_details:
         case_map[cd] = []