Performance Max is a Google Ads campaign type that uses Google’s AI to serve ads across Search, Shopping, YouTube, Display, Discover, Gmail and Maps from a single campaign. Its common mistakes come from weak inputs: wrong conversion goals, thin assets, no audience signals and no brand controls. Fixing those inputs usually matters more than any bidding tweak.
Mistake 1: Optimizing for the wrong conversions
Performance Max will find whatever you tell it to find. If page views, newsletter sign-ups and purchases are all set as primary conversions with equal value, the system may chase cheap sign-ups and call it success. This is the most expensive mistake because everything else builds on it.
- Set only the true business outcome as primary, such as purchases or qualified leads
- Move micro-conversions to secondary in Goals, then Conversions
- Assign conversion values, even estimated ones, for lead types
- Import offline conversions from your CRM where leads close offline
- Check that enhanced conversions are set up to improve measurement
Mistake 2: Letting brand traffic inflate results
Performance Max can serve ads on your own brand searches. Those users were likely to buy anyway, so results look strong while incremental value is low. Google now offers brand exclusions at the campaign level, using brand lists, so you can keep brand search in a dedicated Search campaign.
Review the search terms insights report and the newer search term reporting for Performance Max to see how much traffic comes from branded queries. If a large share is brand, add exclusions and watch total conversions across all campaigns, not just this one.
Mistake 3: Thin or mismatched assets
An asset group needs headlines, descriptions, images, logos and ideally video. When video is missing, Google may create one automatically from your images, and the result is often poor. When images are generic, ads on Display and Discover look like everyone else’s.
- Provide the full set of headlines and descriptions with varied angles: price, benefit, proof, urgency
- Upload square, landscape and portrait images
- Add at least one real video in landscape and vertical formats
- Build separate asset groups for distinct product lines or audiences
- Review asset performance ratings and replace low performers every few weeks
Mistake 4: Ignoring audience signals
Audience signals are suggestions, not strict targeting. Even so, they help the system learn faster, especially in new accounts. Customer lists, website visitors and custom segments built from search terms you know convert give it a better starting point.
Without signals, the first weeks can drift toward broad, low-value traffic. With them, learning tends to settle sooner. Update the signals as you learn which segments perform.
Mistake 5: A messy product feed
For retail, the Merchant Center feed is the most important asset. Titles, images, prices, availability and product categories decide where and how products appear. A title such as ‘Model X-200’ tells Google little; ‘Women’s waterproof hiking boot, leather, sizes 36 to 42’ tells it a lot.
- Write titles with brand, product type, key attribute and size or color
- Fix disapproved items in Merchant Center diagnostics weekly
- Use custom labels for margin, bestseller or seasonal groups
- Split listing groups so best sellers and low-margin items do not share one budget
Mistake 6: Changing things too often
Performance Max has a learning period after launch and after major changes. Changing budget sharply, swapping all assets or editing conversion goals every few days resets learning and makes results noisy. Agencies set a change calendar: big changes no more than every two weeks, and budget moves in modest steps.
Mistake 7: Running it without negative controls
Advertisers can now add negative keywords to Performance Max campaigns, within limits, and account-level negative lists also apply. Content suitability settings and placement exclusions at the account level help keep ads away from sites and apps that do not fit the brand. Many accounts never set any of these.
How do agencies structure Performance Max?
Structure follows business goals. A store with high and low margin products might run separate campaigns with different ROAS targets. A lead generation business might separate services with different lead values. One campaign for everything is simple but makes it hard to steer budget where profit is.
A practical structure
- Brand Search campaign kept separate, with brand excluded from Performance Max
- Performance Max per profit tier or main category
- Asset groups per product theme or audience
- Standard Shopping or Search campaigns kept for key terms that need tight control
How Alien Road applies Performance Max
In a typical engagement we start with a measurement audit before touching campaigns: conversion actions, values, enhanced conversions, CRM imports and consent mode. Next comes a feed audit in Merchant Center and an asset review. Only then do we build or restructure campaigns, with brand exclusions, audience signals and asset groups mapped to the product catalog.
After launch, the team follows a fixed change calendar and reviews asset ratings, search term insights and placement reports. Monthly reports show results per campaign and across the whole account, including brand Search, so the client sees incremental growth rather than numbers moved from one campaign to another.
Mistake 8: Judging results on platform data alone
Google Ads reports conversions it can attribute to its own ads. Performance Max often looks strong in that view because it reaches people across many surfaces, including those who were already close to buying. The real question is whether total business results grew.
Compare platform-reported conversions with orders or qualified leads in your own system. Watch new customer rate, not just total purchases; Performance Max offers a new customer acquisition goal for that purpose. For larger budgets, a conversion lift study or a geographic holdout gives a cleaner answer than any dashboard.
- Match Google Ads conversions to backend orders weekly
- Track new versus returning customers from the campaign
- Review total account results, not one campaign in isolation
- Run a holdout or lift test before major budget increases
Where to start this week
Open Goals in your Google Ads account and list every primary conversion. If anything other than your real outcome is primary, move it to secondary. Then check whether brand exclusions are set on your Performance Max campaigns. Those two checks take thirty minutes and often fix the biggest problem in the account.
Keep reading: Google Advertising · AI Advertising Optimization