The #1 mistake in your PMax campaign setup!

Super Bowl season is here. And just like in football, a solid game plan makes all the difference. If you step onto the field with no strategy, you’re not optimizing—you’re hoping for a Hail Mary. In this article we’re tackling the biggest mistakes you can make in your PMax setup — the worst part? Most of it is self-inflicted.

The illusion of simplicity.

Automation is supposed to make life easier. But automation without structure doesn’t create efficiency—it creates chaos.

To all you fantasy football nerds out there—you know that just drafting the highest-ranked players doesn’t guarantee a winning season.

If you let the auto-draft bot pick your team, you might end up stacked with strong quarterbacks and no strong running backs.

Or worse—you’ve got star players but no depth, leaving you scrambling when bye weeks hit.

Mistake 1: PMax runs wild

PMax is the same. If you let Google’s algorithm draft your lineup, it’ll chase quick wins—prioritizing cheap conversions (short passes) instead of building a strategy that actually wins in the long run.

Out-of-the-box, Google wants you to run a PMax setup that throws all your players into one basket so they can duke it out among each other. Only the strongest performers succeed.

  • Google fixates on your best-sellers – they get all the budget. Everything else? Ignored.
  • Longtail products disappear – New, niche, or high-margin items never get a chance.
  • ROAS looks great, but profits suffer – low-value products eat your ad spend while higher-margin ones are sidelined.

Imagine you run an outdoor gear store:

  1. Your best-selling $10 hiking socks dominate your PMax campaign because they convert easily.
  2. Meanwhile, your $250 hiking boots—which actually drive profit—never see the ball.

Your ROAS looks fantastic, but your profit margins shrink, stock levels become misaligned, and your ad spend is stuck in a loop of low-value conversions.

Or in other words: PMax isn’t playing to win. It’s just trying to complete passes.

Mistake 2: A half-baked strategy

Now, many retailers know well enough to avoid the trappings of mistake #1.

Instead, they attempt to introduce some structure by segmenting products based on a single attribute, like margins or past performance.

While definitely a better approach than a product free-for-all, this leads to a glaring issue that usually happens in one of two ways:

1. Segmenting by one attribute (e.g., margins)

You separate high-, mid-, and low-margin products, expecting bigger profits. But:

  • Clicks ≠ sales – We’ve noticed on average 50% of clicked products aren’t purchased.
  • Margin ≠ demand – A high-margin product won’t sell if no one wants it.
  • Basket effects are ignored – PMax doesn’t see when a low-margin item leads to a high-margin upsell.
Pushing high-margin items leads them to participate in more auctions. It says nothing about their purchase status!

2. Segmenting by past performance (e.g., volume vs. efficiency)

You group products by sales history, assuming past winners will stay winners. The issues?

  • Most products get ignored – 80-90% of your catalog stays underfunded.
  • Overspending on past stars – 1-3% of products hog the budget, even if demand is fading.
  • New products stay benched – If it’s not already performing, PMax won’t push it.

Back to our outdoor gear store:

  1. You break out campaigns for high-, mid-, and low-margin products, thinking this will increase profitability.
  2. But Google still pours budget into high-volume, low-margin items like socks.
  3. Your high-end hiking boots—your real moneymakers—are still benched.

Congratulations! Your ad spend is slightly more efficient, but you’re still not steering your strategy towards the profitable finals!

You might overspend on products (#4) that don’t need much help while neglecting products with little data (#1). 

So, how ‘do’ I play in the big league?

Here’s a hint: Fantasy football pros don’t draft based on one stat—they build a balanced team.

PMax is no different. Instead of relying on a single segmentation factor, you need to integrate smarter data—profit margins, inventory levels, customer lifetime value, and more—to give Google’s AI the right guidance.

But knowing what to fix is only half the battle. How do you actually structure PMax for maximum profitability?

Check out our Ultimate PMax Optimization Playbook for an in-depth guide on how to set up campaigns that actually align with your business goals: 

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READ: The ultimate PMax setup guide!

🚀 2025 is PMax’s biggest year yet—so make sure you’re ahead of the curve!

Performance Max has come a long way, but it’s still not perfect. With big updates dropping fast, the question isn’t if you should adapt—but how.

Mike Ryan’s latest webinar breaks down what’s new, what’s better, and what might just be worse, saving you the headache of figuring it out alone.

📺 Watch now: PERFORMANCE MAX 2025: WHAT’S NEW FOR YOUR ECOMMERCE STRATEGY