diff --git a/tagged-structure-merger/src/main/java/org/verapdf/tools/tagged/StructureRuleCreator.java b/tagged-structure-merger/src/main/java/org/verapdf/tools/tagged/StructureRuleCreator.java
index 160662a..e99400f 100644
--- a/tagged-structure-merger/src/main/java/org/verapdf/tools/tagged/StructureRuleCreator.java
+++ b/tagged-structure-merger/src/main/java/org/verapdf/tools/tagged/StructureRuleCreator.java
@@ -161,7 +161,7 @@ private Rule getRuleAboutStructTreeRoot(List<Reference> annex_l_reference, int t
 				StructureTag.STRUCTURE_TAG.getTag(),
 				"The logical structure of the conforming file shall be described by a structure hierarchy rooted " + 
 						"in the StructTreeRoot entry of the document catalog dictionary, as described in ISO 32000-2:2020, 14.7",
-				"StructTreeRoot_size == 1",
+				"containsStructTreeRoot == true",
 				Profiles.errorFromValues("StructTreeRoot entry is not present in the document catalog", Collections.emptyList()),
 				annex_l_reference);
 	}