In Advanced Analytics formulas, why do I need to wrap fields in an aggregative function?

Question

In AVA, I sometimes get an error: "Invalid Formula - missing aggregative function" when creating a measure (value). Why?

Answer

Any field you place in the Values section needs to be wrapped in an aggregate function because Advanced Analytics has to know how to combine multiple rows of underlying data into a single figure.

Take a pivot table grouped by Project Name. A single project may have several underlying records behind that value, and without a function such as SUM, COUNT, MAX or MIN there's no rule for turning those records into the one number the cell has to display.

This applies even when a group contains only one record, since Advanced Analytics validates the formula itself rather than inspecting the data behind it.