I am trying to calculate a Volume Change metric for a column graph. An abbreviated version of my table looks like this:
Geography Time Period Target Volume
Boston QTD ONC 33
Boston 1 Month ONC 21
Boston 3 Month ONC 34
Boston QTD OTHER 23
Boston 1 Month OTHER 17
Boston 3 Month OTHER 22
New York QTD ONC 43
To achieve a total volume metric, my expression looks something like this:
But now I want to do a Volume Change metric: (Current Time Period Volume - Prior Time Period Volume) / Prior Time Period Volume
How would I go about achieving such an expression with my current table setup??
I have a feeling that I would need to add another column for 'Previous Volume' but I do not really want to do this.
Any/all help is most appreciated.