Google’s Performance Max is changing the way we think about paid media. It is powerful, automated and highly effective. But if you want to get the very best out of it, you need more than great creative and budget - you need better measurement. Here’s why the smartest marketers are pairing PMax with independent insight.
Google Performance Max (PMax) has moved from an “interesting new format” to one of the most important growth engines in paid media. It represents one of the most advanced applications of AI in advertising: a fully integrated, cross-channel system that helps marketers reach customers wherever they are across Google’s ecosystem.
Search. Shopping. YouTube. Display. Gmail. Maps. All managed through a single campaign, powered by one of the most sophisticated machine learning engines in the world. For brands looking to scale efficiently, that is a breakthrough.
The numbers back that story up. Fospha’s Peak Playbook 2025 shows that Performance Max and Paid Search together made up almost 40% of brands’ total channel mix in 2024, and that during BFCM 2024 brands saw 22% better Paid Search ROAS year on year and 71% more revenue generated through PMax, with 58% of conversions from these two channels coming from new customers.
In other words, Google’s demand capture stack is not just big. It is getting more effective at bringing in net new customers when it matters most.
One of the more useful patterns in the data is how the best brands allocate budget inside Google. In another playbook – Fospha’s Performance Max & Google Search Playbook, the top 25% of retail brands by blended ROAS allocate around 55% of their Google budget to PMax and 12% to Paid Search, with smaller brands leaning 52 / 15 and larger brands closer to 59 / 9 in favor of PMax.
That split is not about choosing automation over control. It reflects a model where:
PMax handles scaled, cross channel demand capture
Generic Search keeps precision and visibility in the highest intent moments
For many advertisers, that combination gives them both reach and control in the same stack.
The playbooks also show that PMax is flexible. It can be used to drive both online sales and in store goals, with store focused campaigns becoming more important as delivery cut off dates approach in peak season.
If PMax is the engine, creative and structure are the fuel. The playbook highlights four simple PMax principles: build a strong asset library across formats and orientations, tell a consistent brand story, structure campaigns and asset groups around products or audiences, and lean into Google’s AI tools for asset generation and testing.
In practice, that means:
Multiple video orientations and image formats so PMax can show up cleanly across YouTube, Discover, Display and more
Asset groups aligned to real product categories or customer segments
Letting Google’s bidding and creative optimisation run long enough to learn, instead of resetting targets every few days
Brands that do this well are the ones able to keep scaling PMax rather than capping it out early.
None of this works without trust. But trust in a black box is easier when you can validate what is happening. That is where independent measurement platforms like Fospha (who operate with a glass box model) quietly support Google rather than compete with it.
Their own data shows that last click attribution underestimates PMax revenue by around 33% and Paid Search revenue by about 59%, despite these channels representing roughly 24% and 9% of the average brand’s wallet.
When marketers look only at last click, they often end up underfunding the very PMax and Search campaigns that are driving growth. Fospha’s measurement approach, built on a daily updating Bayesian MMM, is explicitly designed to give brands a full funnel, cross channel view of incremental impact while staying privacy safe. That independent view does something important for Google’s ecosystem: it often proves that PMax is working better than platform reporting alone suggests, and shows where there is still room to grow.
In their latest report, Fospha estimates there is on average about 61% profitable growth headroom still available across PMax and Paid Search for the brands in its dataset. In real terms, that is exactly the kind of signal that lets them move more budget into PMax and Search with confidence rather than hesitation.
We’re entering a phase where Google’s AI drives performance and independent measurement AI proves the impact.
One engine finds the right customers at the right moments. The other gives marketers the clarity and confidence to invest smarter. Together, they push marketing forward.
PMax represents the future of digital advertising: automated, intelligent, always learning, and powered by Google’s unmatched ecosystem. Early adopters are already pulling ahead, and those who pair PMax with robust, independent measurement gain the ultimate advantage: the ability to scale boldly, backed by true, full-funnel clarity. The future is bright, and right now the data suggests there is still a lot of room to run.
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