- Why ROAS lies
- What MER measures
- Setting MER targets
- Attribution reality
- FAQs
Why ROAS lies
Platform ROAS (Meta, Google) uses their attribution windows and their view of conversions. iOS 14 broke a lot of this. Now Meta over-attributes, Google over-attributes, and you triple-count.
A "3x ROAS on Meta" often means 1.8x when you look at bank deposits.
What MER measures
MER = Total Revenue / Total Ad Spend
Blended. All channels. Bank-verified. It's what the CEO and CFO see.
If your MER is 2.5x and your CM at 2.5x MER is positive — you're growing profitably. It doesn't matter what Meta says.
Setting MER targets
Work backwards from CM. If your CM before ad spend is 40%, your MER breakeven is 2.5x. Your target should be 3x+.
Attribution reality
Run weekly incrementality tests. Turn off channels for a week. See what happens. Attribution is a model — incrementality is truth.
FAQs
Q: How often should I review MER?
Weekly. Daily during scaling sprints.