diff --git a/package.json b/package.json
index 175b667..65141ac 100644
--- a/package.json
+++ b/package.json
@@ -43,6 +43,7 @@
     "@openactive/data-model-validator": "^2.0.0",
     "cache-parser": "^1.2.4",
     "jsonpath": "^1.1.1",
+    "lodash": "^4.17.21",
     "luxon": "^1.4.2",
     "node-fetch": "^2.2.0"
   }
diff --git a/src/rules/page/required-property-values-rule.js b/src/rules/page/required-property-values-rule.js
index 36d5b5c..7b42db1 100644
--- a/src/rules/page/required-property-values-rule.js
+++ b/src/rules/page/required-property-values-rule.js
@@ -1,3 +1,4 @@
+const _ = require('lodash');
 const {
   ValidationErrorCategory,
   ValidationErrorSeverity,
@@ -141,8 +142,7 @@ const RequiredPropertyValuesRule = class extends RpdeRule {
     if (node.data.items instanceof Array) {
       for (const item of node.data.items) {
         if (
-          typeof item !== 'object'
-          || item instanceof Array
+          !_.isPlainObject(item)
         ) {
           invalidProps.item += 1;
         }
@@ -172,7 +172,7 @@ const RequiredPropertyValuesRule = class extends RpdeRule {
         }
         if (
           typeof item.data !== 'undefined'
-          && (typeof item.data !== 'object' || item.data instanceof Array)
+          && !_.isPlainObject(item.data)
         ) {
           invalidProps.data += 1;
         }