Google adds cross-campaign testing with new Mix Experiments beta

Google Ads is rolling out Campaign Mix Experiments (beta), a new testing framework that lets advertisers test multiple campaign types, budgets, and settings within a single, unified experiment.

How it works. Advertisers can create up to five experiment arms, each with a different mix of campaigns.

• Campaigns can appear in multiple arms, with traffic split between them.
• The experiments support Search, Performance Max, Shopping, Demand Gen, Video, and App campaigns (excluding Hotels).
• Advertisers can customize traffic splits with a minimum of 1%, and results are normalized to the lowest split to ensure fair comparison.

What you can test:

• Budget allocation across campaign types.
• Account structure, including consolidation vs. fragmentation.
• Bidding strategies, targeting, and feature adoption.
• Cross-channel performance interactions, not just single-campaign lift.

Why we care. Instead of testing Search, Performance Max, Demand Gen, or Video campaigns in isolation, you can now see how different campaign types work together and which mix delivers the strongest business results.

Reporting details. Results appear in the experiment summary and campaign-level reports, where advertisers can choose confidence intervals (95%, 80%, or 70%) and primary success metrics such as ROAS, CPA, conversions, or conversion value.

Best practices:

• Keep experiment arms similar and change only one variable at a time.
• Align total budgets across arms unless budget is the variable you are testing.
• Avoid shared budgets and major in-flight changes.
• Run experiments for at least six to eight weeks to achieve statistical reliability.

Between the lines. This is Google acknowledging that modern performance isn’t about winning one campaign — it’s about finding the right mix, especially as automation blurs the lines between channels.

Bottom line. Campaign mix experiments give you a clearer, more realistic way to test how campaign types and budgets work together and make smarter decisions about where spend truly delivers incremental value.

The Google Ads help doc. About Campaign Mix Experiments (Beta)