diff --git a/modules/saml/lib/Auth/Source/SP.php b/modules/saml/lib/Auth/Source/SP.php
index 2421fe654c4ef19c3b82650bdc4cec946fa53f18..12fb37aea02169ae6483ac8a99535ce02c764ee0 100644
--- a/modules/saml/lib/Auth/Source/SP.php
+++ b/modules/saml/lib/Auth/Source/SP.php
@@ -47,7 +47,7 @@ class sspmod_saml_Auth_Source_SP extends SimpleSAML_Auth_Source {
 		/* Call the parent constructor first, as required by the interface. */
 		parent::__construct($info, $config);
 
-		if (!array_key_exists('entityID', $config)) {
+		if (!isset($config['entityID'])) {
 			$config['entityID'] = $this->getMetadataURL();
 		}