diff --git a/question/classes/statistics/responses/analysis_for_class.php b/question/classes/statistics/responses/analysis_for_class.php
index 872f020e603..efb7d7b5438 100644
--- a/question/classes/statistics/responses/analysis_for_class.php
+++ b/question/classes/statistics/responses/analysis_for_class.php
@@ -145,7 +145,7 @@ class analysis_for_class {
             return true;
         } else if (count($actualresponses) === 1) {
             $singleactualresponse = reset($actualresponses);
-            return (string)$singleactualresponse != $this->modelresponse;
+            return (string)$singleactualresponse !== (string)$this->modelresponse;
         }
         return false;
     }