jjefferson,
Thanks for the reply! After a lot of research, I finally came to the same result. I put the CASE sequence in my WHERE clause of the data query. Because I wanted to use "Status" as a parameter, I also had to add it to the SELECT clause of my parameter query. I used DISTINCT in the parameter query to avoid having 12 "closed" and 12 "open" choices in the prompt on the interface.
On the interface, the status field is a checkbox, so there are only two possible results. No problems there.
It was such a relief when it worked.
Thanks again!