Making variable value execute as an expression

[#1]

Hello! I am trying to create and execute a dynamic expression for each KPI based on the hospital department a user selects. I was able to create an expression dynamically but could not get it to execute.

The following expression:

=Concat({$<[KPI Rank] = {'1'} >} MetText) results in

count(DISTINCT [ACCOUNT_NBR_ENC]).

How do I use a nested aggregation to make this value evaluate? I would like to see a numeric value.
In the example above, I would like to see the result of 'count(DISTINCT [ACCOUNT_NBR_ENC])'. Any help is appreciated. I have attached my application.

Thanks

[rwunderlich · Accepted solution]

It looks like you answered your own question in your posted example. .

=$(=only({$<[KPI Rank] = {'1'} >} MetText))

I'd prefer only() over concat() in this example unless you are actually trying concat multiple values.

[#3]

Thank you