If your agency's monthly report leads with ACoS, you are being managed to the wrong number.
I say this as someone who runs an agency. The report is where the honesty either shows up or hides.
ACoS is a useful diagnostic and a terrible headline. It goes down when you stop advertising. It goes down when you cut discovery. It goes down right before your organic rank starts sliding.
You can win ACoS for three months and be a smaller brand at the end of it.
What we put at the top of a report instead
Total revenue and contribution margin, because that is the business.
TACoS, total ad spend against total revenue, because it shows whether ads are building organic strength or replacing it.
New-to-brand orders and repeat rate, because that is future revenue.
Organic rank on the keywords that matter, because that is the asset you are building.
Then ACoS, in context, as one lever among several.
Optimized into decline
A brand came to us from another agency with a beautiful trend line. ACoS had gone from 29% to 19% over five months. The previous agency called it a win.
Total revenue was down 22% in the same window and their top three keywords had fallen off page one. They had been optimized into decline.
A report should be able to deliver bad news. If every month looks like progress, the metrics were chosen to make sure of it.
Does your reporting tell you the truth, or tell you a story?