diff --git a/editions/tw5.com/tiddlers/filters/haschanged.tid b/editions/tw5.com/tiddlers/filters/haschanged.tid
index 25dfd515e..185f19eb7 100644
--- a/editions/tw5.com/tiddlers/filters/haschanged.tid
+++ b/editions/tw5.com/tiddlers/filters/haschanged.tid
@@ -4,12 +4,12 @@ tags: [[Filter Operators]] [[Negatable Operators]]
 title: haschanged Operator
 type: text/vnd.tiddlywiki
 caption: haschanged
-op-purpose: returns input titles where the corresponding tiddlers have changed since startup
+op-purpose: filter the input by tiddler modification status
 op-input: a [[selection of titles|Title Selection]]
 op-parameter: none
-op-output: those input tiddlers that have not changed since startup
-op-neg-output: those input tiddlers that have changed since startup
+op-output: those input tiddlers that have been modified during this session
+op-neg-output: those input tiddlers that have <<.em not>> been modified during this session
 
-Each input title is processed in turn, and is returned if any of its fields have changed since startup (or, with negation, if it has not changed).
+A tiddler is deemed to have been modified if it has been written back to the wiki since the start of the current ~TiddlyWiki session. If you edit a tiddler and immediately store it again without making any changes, that is enough to mark it as modified.
 
-<<.operator-examples "haschanged">>
+<<.operator-examples "haschanged">>
\ No newline at end of file