Definition
PMax cannibalization is when Performance Max spends budget on, and credits itself for, conversions that would have happened regardless (typically brand searches and bestsellers), so its reported performance is artificially inflated.
Also called: PMax cannibalization, Performance Max cannibalization, PMax self-attributionProduct data becomes a Shopping ad.
- title
- Organic Tee · Green
- availability
- in_stock
- price
- 40.00 EUR
- color
- green
- size
- M
Choose a variant. The product data and ad update together.
Organic Tee · Green
€40In stock · Example priceFrom Cobiro01ID, title, image and variant describe the actual product being sold.
Why PMax looks better than it is
Left to its own devices, Performance Max gravitates toward the easy and cheap: brand searches and bestsellers, where conversion rates are high. The problem is that most of that demand already existed. PMax doesn't create it, it harvests it, then takes the credit in the report. The result is an inflated PMax ROAS and an undervalued prospecting effort.
The fix is to build guardrails: brand exclusions so PMax stops bidding on brand searches, a separate brand campaign, and judging PMax on incrementality and MER instead of attributed ROAS. Otherwise you shift budget toward what looks best rather than what actually drives growth.
Frequently asked questions
How do I avoid PMax cannibalization?
Exclude brand searches from Performance Max (brand exclusions) or run a separate brand campaign, and judge PMax on incrementality and MER instead of attributed ROAS. That way you see the real, created value rather than harvested demand.
Does cannibalization mean I shouldn't use PMax?
No. PMax is effective when it's controlled. The problem isn't the campaign type, it's letting it run without guardrails. With brand exclusions and a profit signal, it becomes a powerful tool rather than a flattering report.
From insight to action
See how it applies in practice.
Advertising across markets
The Colorful Standard case connects account structure, product feeds and local demand. Explore the work and the considerations behind it.
Read the caseGoogle Ads
Discuss your Google Ads
We discuss your goals and measurement to identify the focus of an account review.
Choose a time30 minutes · No obligation
About the author
Malthe Ærbo Weibeck
Pull specialist with 8+ years' experience. Comes from the agency world and has since worked as an independent consultant for several of the country's largest brands.
Meet the team