Without knowing more about the problem it's hard to say why this isn't working, but values in a Tagged column should work just fine in a calculated column expression. The one issue that does come up sometimes if for "Untagged" values. When trying to create a calculated column using an expression like:
IF([tagged column] = "Untagged","Fail","Pass")
All of the values in the new column are set to "Pass", as if Spotfire doesn't recognize any of the "Untagged" values.
Resolution: A status of "Untagged" is seen as a blank field in Spotfire, so you have to access in that manner. You would use: