Without proper brand exclusions, PMax claims credit for customers who were already searching for your brand name. You're paying $2-5 CPCs for traffic that would have cost $0.50 through a dedicated brand campaign. This inflates PMax ROAS while hiding true customer acquisition costs. We've seen stores where 80%+ of PMax 'conversions' were actually branded searches.
Example: PMax showing ads for 'yourstore.com' and 'yourstore reviews'
Shopify's default Google channel app exports basic product data, but misses custom labels, product highlights, sale prices, and proper GTIN formatting. Without these, your products lose Shopping auction eligibility and show lower in results. Product titles pulled directly from your store often lack the keywords customers actually search for—like 'men's' or 'women's', material type, or size indicators.
Example: Products missing 'sale_price' during promotions, titles like 'Hoodie Size M' instead of 'Men's Cotton Hoodie'
Running 500+ products in one PMax asset group means Google optimizes for aggregate ROAS by heavily serving your top 20 products. The other 480 get almost no impressions. Worse, low-margin products can drag down your overall profitability while appearing successful in aggregate. Without product segmentation, you can't scale winners or cut losers.
Example: 80% of impressions going to 5% of products, new arrivals getting zero visibility
With a single asset group, Google optimizes for aggregate ROAS by heavily favoring your top 5-10 products. The rest of your catalog gets almost no impressions. Worse, low-margin products drag down profitability while appearing successful in aggregate.
Fix: Segment products by performance tier: Winners (scale), Potentials (test), Underperformers (cut or fix). Create separate asset groups for each.
PMax claims credit for brand searches that would've cost $0.30 through a dedicated brand campaign. Without exclusions, you're paying 3-5x more for customers already looking for you.
Fix: Add brand exclusions to PMax and run a separate Brand Search campaign with exact match keywords.
Missing GTINs, generic titles, no custom labels, and missing sale prices hurt your Shopping ad performance. Generic product titles from Shopify
Fix: Use all 150 characters in product titles—frontload with searchable terms
Your 5x ROAS might look great until you realize 70% of sales are repeat customers who would've bought anyway. You're paying to acquire customers you already have.
Fix: Segment reporting by new vs returning customers. Set up customer match lists and analyze true CAC.
Not all campaign types work for shopify stores. Here's what to skip:
CPCs too high for most Shopify AOVs under $100
Low intent, poor conversion—save for retargeting only
Prevents optimization by product performance tier
Follow these best practices to maximize your Shopify Google Ads performance:
Budget: 15-20% • Target ROAS: 8-15x
Budget: 50-60% • Target ROAS: 3-5x
Budget: 15-20% • Target ROAS: 4-6x
Budget: 10-15% • Target ROAS: 6-10x