Error in set modifier ad hoc element list

[Newbie777]

Hello,

I am trying to add a yellow highlighted set expression to limit the headcount measure to the one at the last date as a default, and making it flexibly adjust the time from the selection of different dates in other visualizations.  While I used [Year] for the field in the yellow highlighted set expression, no error message appears, but when I replace it with the actual field [Data Copy], I get an incomprehensive error message saying "error in set modifier ad hoc element list: ',' or ')' expected".  

I'd appreciate it if anyone could let me know how I can clear this error message.  

Thank you & best regards,

[MarcoWedel · Accepted solution]

maybe it's the missing single quotes:

{$<[Date Copy]={'$(=max([Date Copy]))'}>}

hope this helps
Marco

[Newbie777]

Thanks a lot Marco.  The error disappeared and set expression is now working perfectly!