diff --git a/app/presenters/admin/collection_presenter.rb b/app/presenters/admin/collection_presenter.rb
index c4b07064bb..7bc4fec13b 100644
--- a/app/presenters/admin/collection_presenter.rb
+++ b/app/presenters/admin/collection_presenter.rb
@@ -44,15 +44,15 @@ def unpublished_media_object_count
   end
 
   def managers
-    @managers ||= document["edit_access_person_ssim"] & (document["collection_managers_ssim"] || [])
+    @managers ||= Array(document["edit_access_person_ssim"]) & Array(document["collection_managers_ssim"])
   end
 
   def editors
-    @editors ||= document["edit_access_person_ssim"] - managers
+    @editors ||= Array(document["edit_access_person_ssim"]) - managers
   end
 
   def depositors
-    document["read_access_person_ssim"]
+    Array(document["read_access_person_ssim"])
   end
 
   def manager_count