Stop optimizing for ACoS. I said what I said. ACoS is an ad efficiency metric. N
By Elizabeth Greene · April 27, 2026 · Curated by George's Blog
Stop optimizing for ACoS.
I said what I said.
ACoS is an ad efficiency metric.
Not a business metric.
Those are not the same thing.
A brand can have 12% ACoS and be completely unprofitable.
A brand can have 38% ACoS and be growing faster than anyone in their category.
Context is everything.
What you should actually be watching:
→ Total ACoS: ad spend against total sales, not just ad sales
→ Organic sales growth: is the ad investment creating lift beyond the ads?
→ Ad sale percentage: is organic share growing or shrinking over time?
ACoS is one signal on a dashboard.
Treating it like the only signal is exactly why so many brands get stuck in a loop they can't explain.
Know what you're optimizing for.
And make sure it connects to something that actually matters.