diff --git a/lib/questionlib.php b/lib/questionlib.php
index 062d4b2e378..eb9b4ca2ac1 100644
--- a/lib/questionlib.php
+++ b/lib/questionlib.php
@@ -357,7 +357,7 @@ function question_delete_question($questionid) {
 
     $questionstocheck = [$question->id];
 
-    if ($question->parent !== 0) {
+    if ($question->parent) {
         $questionstocheck[] = $question->parent;
     }