Use Filters in Measure DAX

I would first try your original measure with ALLSELECTED() instead of ALL().

If this works for you, please mark it as solution.  Kudos are appreciated too.  Please let me know if not.

Regards,

Pat

Hi DHB ,

You may try to use the below measure:

DIVIDE(COUNT(ACTIVITY[PERSON_CODE]),CALCULATE(COUNT(ACTIVITY[PERSON_CODE]),ALLSELECTED(ACTIVITY)))

 Please try.

Aiolos Zhao