diff --git a/module/VuFind/src/VuFind/Recommend/AuthorityRecommend.php b/module/VuFind/src/VuFind/Recommend/AuthorityRecommend.php
index 9dc4887b472650a6efd4b8fce60d1d8f303ebd08..08c62ef023411ad8faede55ec0e309ab366ed671 100644
--- a/module/VuFind/src/VuFind/Recommend/AuthorityRecommend.php
+++ b/module/VuFind/src/VuFind/Recommend/AuthorityRecommend.php
@@ -282,7 +282,7 @@ class AuthorityRecommend implements RecommendInterface
         $this->results = $results;
 
         // empty searches such as New Items will return blank
-        if ($this->lookfor == NULL) {
+        if ($this->lookfor == null) {
             return;
         }