If you have mastered the basics of Performance Max, it is time to go deeper. This guide covers advanced strategies for scaling PMax campaigns while maintaining profitability — from multi-campaign architectures to sophisticated asset testing frameworks.
Multi-Campaign PMax Architecture
A single PMax campaign with a single asset group is the starting point, not the destination. As your budget grows beyond €5,000/month, a multi-campaign architecture delivers better performance by allowing granular budget control and tailored optimization targets.
We recommend three campaign tiers:
Tier 1 — Hero Products Campaign. Dedicated to your top 20% of products by margin contribution. Set an aggressive tROAS target (lower than your blended target) because these products can afford higher CPAs. Use dedicated creative assets that showcase product quality, reviews, and unique selling points. Budget allocation: 40-50% of total PMax spend.
Tier 2 — Core Catalog Campaign. Covers your mid-range products with moderate margins. Use a balanced tROAS target that reflects your overall profitability goal. Group products into asset groups by category to allow category-specific creative. Budget allocation: 30-40% of total PMax spend.
Tier 3 — Long Tail Campaign. Handles your remaining catalog with conservative tROAS targets. Use fewer creative assets (generic category images suffice) and focus on feed quality rather than creative differentiation. Budget allocation: 10-20% of total PMax spend.
This architecture prevents high-margin products from competing with low-margin ones for the same budget. It also allows you to scale budget on profitable segments without dragging performance down with underperforming products.
Search Themes and Keyword Intent
Search Themes, introduced in late 2023, are the closest thing to keyword targeting in PMax. They allow you to suggest search intent categories that your campaign should target, giving Google's algorithm a stronger starting signal.
Effective Search Theme strategy involves:
Category-level themes. Add Search Themes that match your product categories. For an electronics retailer, themes might include "wireless headphones," "laptop deals," and "gaming monitor reviews." Keep themes specific enough to signal intent but broad enough for Google to find relevant queries.
Competitor-adjacent themes. Include themes related to competitor brands and their product categories. This positions your ads in comparison-shopping queries where users are evaluating alternatives. Be strategic — target competitors where your products have clear advantages.
Problem-solution themes. Add themes that describe the problems your products solve rather than the products themselves. "Best headphones for working from home" captures intent that product-category themes might miss.
Negative themes. While PMax does not support negative keywords in the traditional sense, you can influence targeting by adding campaign-level brand exclusions and account-level negative keyword lists. This prevents PMax from bidding on irrelevant queries.
Review Search category insights monthly to understand which search themes drive conversions and refine your theme list accordingly. Remove themes with high spend but low conversion rates, and add new themes based on successful queries you discover.
Asset Group Testing Framework
Creative testing in PMax requires a structured approach because you cannot A/B test individual assets in isolation. Instead, we use an asset group rotation framework.
Week 1-2: Baseline. Launch your asset group with your best-performing creative assets (based on prior campaign data or creative brief). Record baseline performance metrics: CTR, conversion rate, CPA, and ROAS.
Week 3-4: Test variant. Create a duplicate asset group with one variable changed. This could be a new headline set, different images, updated video assets, or modified descriptions. Run both asset groups simultaneously with equal budget.
Week 5: Analyze and decide. Compare performance between the baseline and test asset groups. If the test variant outperforms, adopt it as the new baseline. If not, revert and test a different variable.
The key rule is testing one variable at a time. Changing headlines and images simultaneously makes it impossible to determine which change drove the performance difference. Test in order of expected impact: video assets first (highest impact), then images, then headlines, then descriptions.
Asset performance ratings in PMax (Low, Good, Best) provide directional signals but should not be your sole decision criteria. An asset rated "Low" might perform well in specific contexts that the aggregate rating does not capture. Always pair asset ratings with your own A/B testing data.
PMax and Standard Shopping Coexistence
Running PMax alongside Standard Shopping campaigns gives you the best of both worlds: PMax's cross-channel reach and automation with Standard Shopping's granular control and search term visibility.
The coexistence strategy we use:
PMax for prospecting and full-funnel. PMax handles upper-funnel awareness (YouTube, Display, Discovery) and broad shopping queries where you want maximum reach. Set PMax tROAS slightly lower than Standard Shopping to allow the algorithm room for prospecting.
Standard Shopping for high-intent queries. Use Standard Shopping for your best-performing product categories with exact product targeting. Standard Shopping gives you full search term reports, bid-by-product control, and the ability to add negative keywords. These campaigns capture high-intent shoppers that PMax might handle less efficiently.
Campaign priority settings. Google automatically prioritizes PMax over Standard Shopping for Shopping inventory. To prevent PMax from cannibalizing your Standard Shopping campaigns, use listing groups in PMax to exclude the specific product categories covered by Standard Shopping.
Budget allocation. Start with a 60/40 split (PMax/Standard Shopping) and adjust based on incremental performance. If Standard Shopping delivers higher-quality traffic at lower CPAs for specific categories, shift budget accordingly.
Monitor overlap by checking impression share and auction insights for both campaign types. If PMax is taking impressions from high-performing Standard Shopping campaigns without improving overall performance, adjust your listing group exclusions.
Scaling PMax Without Killing Efficiency
Scaling PMax budget while maintaining ROAS requires patience and a systematic approach. Rapid budget increases reset the learning phase and cause performance volatility.
The 20% rule. Never increase budget by more than 20% in a single adjustment. For a campaign spending €100/day, increase to €120/day, wait 1-2 weeks for stabilization, then increase to €144/day. This allows the algorithm to gradually expand targeting without a performance cliff.
tROAS stepping. As you scale budget, you may need to relax your tROAS target to give the algorithm more room. A common approach is to lower tROAS by 10-15% when increasing budget by 20%. Once the higher budget stabilizes, gradually tighten tROAS back toward your target.
Audience signal expansion. As you scale, broaden your audience signals to give PMax a larger pool to work with. Add new customer match lists, expand custom segments, and include broader in-market audiences. More signal data helps the algorithm find profitable audiences at higher spend levels.
Creative refresh. Higher budgets mean faster creative fatigue. Increase your creative refresh cadence from monthly to bi-weekly when spending above €10,000/month. Monitor click-through rates as an early indicator of creative fatigue — a declining CTR often precedes CPA increases.