Google Performance Max: The Hidden Settings That Actually Work

Google Performance Max campaigns have divided opinion since their 2021 launch. Advertisers either achieve strong results and swear by them, or waste significant budget and conclude they do not work. In our experience managing PMax across dozens of accounts, the difference between these two outcomes almost always comes down to setup, not the campaign type itself. Here are the specific settings that consistently move the needle.

The Core Problem: Default PMax Optimises for the Wrong Thing

Out of the box, Performance Max will serve ads across every Google surface — Search, Shopping, Display, YouTube, Gmail, Maps, and Discover — with minimal advertiser control over budget allocation. Without proper configuration, it systematically prioritises easy, cheap conversions: branded searches from people already planning to buy from you, and existing customers making repeat purchases. The result is artificially high ROAS numbers that do not represent genuine new customer acquisition.

Setting 1: Brand Exclusions — The First Thing You Must Do

Before anything else, exclude your brand terms. Navigate to Campaign Settings → Brand Exclusions and add every variation of your brand name: full name, common abbreviations, misspellings, and product names that are closely associated with your brand. This forces Performance Max to compete for genuinely new customers rather than simply capturing branded search traffic that would have converted anyway.

Your reported ROAS will drop after implementing brand exclusions. This is the correct outcome. The number you see after the exclusion is a more accurate representation of what PMax is actually generating in incremental value. The inflated ROAS you had before was largely brand attribution.

Setting 2: Customer Match — Exclude Your Existing Customers

Performance Max will, by default, eagerly target your existing customers with acquisition-focused bidding strategies. This inflates conversion numbers and ROAS while costing you acquisition budget on people who would have purchased anyway. Upload your customer email list as a Customer Match audience and use it as an exclusion audience, not a targeting signal.

If you want to run retention campaigns through Google, create a separate campaign specifically for that purpose with different budgets, objectives, and ROAS targets. Mixing acquisition and retention in the same campaign makes performance analysis impossible and budget allocation inefficient.

Setting 3: Audience Signals — Quality Over Quantity

Audience signals are suggestions to Google's algorithm about where to start looking for customers — they are not hard targeting restrictions. The quality of your signals matters significantly. The highest-value signals are: your customer email list (particularly your top 20% of customers by lifetime value), website purchasers, and high-intent custom segments (people who have searched for specific terms related to your product).

Do not add broad interest categories as signals. Generic audiences like "online shoppers" or "travel enthusiasts" add noise without meaningful direction. The algorithm is already better at identifying relevant users than generic interest targeting — give it your first-party data and let it work from there.

Setting 4: Asset Group Structure — One Group Is Never Enough

The majority of PMax accounts we audit have a single asset group containing all creatives for the campaign. This is a consistent source of underperformance. Structure your asset groups by product category, audience intent level, or campaign objective so that Google can match the most relevant creative to the most relevant search or browse behaviour.

For an e-commerce brand with three product lines, build three asset groups — one per product line — each with headlines, descriptions, images, and videos specific to that product. For a service business, build separate asset groups for each service and each stage of the funnel (awareness versus consideration versus conversion-ready). This specificity consistently improves relevance scores and conversion rates.

Setting 5: Final URL Expansion — Usually Turn It Off

Final URL Expansion allows Performance Max to redirect your ads to any page on your website that it determines is relevant to the user's query — not just the URL you specified. In theory this is beneficial. In practice, it frequently sends traffic to low-converting pages: blog posts, category pages with poor product coverage, or even the homepage when a specific product page would convert better.

Unless every page on your website is high quality and well-optimised for conversion, turn Final URL Expansion off. You lose some potential reach, but you gain control over the user experience after the click — and that is where the revenue is made.

Setting 6: Bidding Strategy Progression

Do not start Performance Max campaigns with Target ROAS bidding. Start with Maximise Conversions and allow the campaign to accumulate a minimum of 50 conversions — ideally 100 — before switching to Target ROAS. This gives the algorithm enough data to model your customer acquisition patterns accurately before you add a ROAS constraint that limits its ability to find customers.

When you do switch to Target ROAS, set a conservative initial target: 20-30% below your current observed ROAS. Aggressive ROAS targets on a campaign with limited data cause significant under-delivery as the algorithm struggles to find enough qualifying traffic. Start conservative, confirm performance stability, then tighten the target incrementally.

The Performance Max Audit Checklist

• Brand terms excluded from campaign targeting
• Existing customer list uploaded and excluded
• Asset groups structured by product category or audience intent — not one single group
• Audience signals using first-party data (customer lists, purchasers)
• Final URL Expansion disabled unless all site pages convert well
• Bidding on Maximise Conversions until 50+ conversions, then Target ROAS
• Separate campaigns for acquisition vs retention
• Search Themes added (available in some accounts) for additional query signal