Using the drop down selections in a Status column as the reference, i've set up a Completion column to indicate how far along a project is.
However, occasionally multiple statuses are needed to appropriately indicate the project's level of completion. I've tried multiple iterations of the below formula to varied degrees of failure. Some arrangements net "Unparseable". Others net "Invalid Data Type". And some do not trigger an error message, but also do not populate the Completion column.
..., STATUS@row = "output" + "invoice"), "Full")))))