Advantage of limiting prompt values by Members of Groups option

Have a look at the values of Region column.

Create a dashboard prompt on Region column and do not include Missing, Not Applicable and UNKNOWN values.

We have used NOT IN clause to eliminated the above values from Region prompt.

Run the prompt.

Go to Search.. option and ensure those values are present or not.

Let us find a solution.

Create a Group.

Take a Region column in the report and go to Selection Steps.

Select Region column from the list.

Edit Member Group. 

Select Action as Remove.

Manually remove UNKNOWN, Missing and Not Applicable from the list.

Do not check override with prompt option.

Save the group at appropriate location in Shared folder.

Now go to Region prompt and include this group.

Perform both the checks and you will find the Missing, Not Applicable and UNKNOWN values completely being eliminated from the prompt.

Thank you.