We built a marketing efficiency ratio calculator. It completely changed how we e
By Adam Weiler · April 24, 2026 · Curated by George's Blog
We built a marketing efficiency ratio calculator.
It completely changed how we evaluate ad spend.
Here's what we discovered:
Looking at channels in isolation kills growth.
Example:
→ Facebook ads: 2.5x ROAS ("too low")
→ Amazon PPC: 4.2x ROAS ("just right")
→ YouTube: 1.8x ROAS ("cut it")
But when we plugged them into the overall equation...
That "low performing" Facebook spend was driving:
→ 34% more Amazon branded searches
→ Higher organic ranking for target keywords
→ 2.1x better lifetime value
The real metric isn't channel ROAS.
It's marketing efficiency ratio (MER) across the entire funnel.
Total revenue ÷ total ad spend = your true performance.
Sometimes spending "past your Amazon target" makes perfect sense.
Because it's fueling brand awareness that creates cheaper future clicks.
The brands scaling past $10M get this.
They optimize for ecosystem performance, not channel performance.
One channel feeds another.
And the flywheel compounds.
How do you measure marketing efficiency across all your channels?