diff --git a/core/modules/filters.js b/core/modules/filters.js
index bc1138990..c9fae0b70 100644
--- a/core/modules/filters.js
+++ b/core/modules/filters.js
@@ -198,7 +198,7 @@ exports.compileFilter = function(filterString) {
 					operand = self.getTextReference(operator.operand,"",currTiddlerTitle);
 				}
 				if(operator.variable) {
-					operand = widget.getVariable(operator.operand,"");
+					operand = widget.getVariable(operator.operand,{defaultValue: ""});
 				}
 				results = operatorFunction(accumulator,{
 							operator: operator.operator,