diff --git a/HTML/QuickForm2/Element/Select.php b/HTML/QuickForm2/Element/Select.php
index 5a2ee07..c18a519 100644
--- a/HTML/QuickForm2/Element/Select.php
+++ b/HTML/QuickForm2/Element/Select.php
@@ -180,7 +180,7 @@ public function getRawValue()
 
         $values = [];
         foreach ($this->values as $value) {
-            if (!$this->data['intrinsic_validation'] || !empty($this->possibleValues[$value])) {
+            if (!$this->data['intrinsic_validation'] || !empty($this->possibleValues[(string) $value])) {
                 $values[] = $value;
             }
         }