diff --git a/ckan/lib/navl/validators.py b/ckan/lib/navl/validators.py
index b67b9367d20..e606c189f5e 100644
--- a/ckan/lib/navl/validators.py
+++ b/ckan/lib/navl/validators.py
@@ -72,8 +72,8 @@ def ignore(key, data, errors, context):
     raise StopOnError
 
 def default(default_value):
-    '''When key is missing or value is 'empty', set it with a default value.
-    See the code for how 'empty' is defined.'''
+    '''When key is missing or value is an empty string or None, replace it with
+    a default value'''
 
     def callable(key, data, errors, context):