diff --git a/pmd-core/src/main/java/net/sourceforge/pmd/properties/modules/NumericPropertyModule.java b/pmd-core/src/main/java/net/sourceforge/pmd/properties/modules/NumericPropertyModule.java
index 36cad41f6d..e728250f48 100644
--- a/pmd-core/src/main/java/net/sourceforge/pmd/properties/modules/NumericPropertyModule.java
+++ b/pmd-core/src/main/java/net/sourceforge/pmd/properties/modules/NumericPropertyModule.java
@@ -39,6 +39,9 @@ public class NumericPropertyModule<T extends Number> {
 
 
     public void checkNumber(T number) {
+        if (number == null) {
+            return; // TODO: remove me when you scrap StatisticalRule (see pull #727)
+        }
         String error = valueErrorFor(number);
         if (error != null) {
             throw new IllegalArgumentException(error);