Performance Max Audit — Make PMax Explain Itself
Performance Max restricts visibility by design. Google intentionally limits what advertisers can see about where their budget goes, which placements convert, and what the algorithm is optimising toward.
This is not a bug. It is how the campaign type works. The question is whether your PMax campaign is generating new customer revenue — or harvesting the brand demand you already own.
viaCMO audits 5 areas Google does not surface. For accounts with significant PMax spend, the findings are often the most consequential in the full report.
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The Problem With PMax
Why PMax Opacity Is a Problem for Australian SMBs
The most significant finding in PMax audits: many SMB Performance Max campaigns succeed primarily by harvesting brand demand. The account converts well because people searching for the business by name are captured by PMax before a standard Search campaign can serve them. Remove PMax, and the branded Search campaign would capture most of those conversions anyway — at the same or lower cost.
This does not mean PMax is wrong for every account. It means the claim that 'PMax is performing well' requires interrogation — because the conversion data Google surfaces does not distinguish between new customer acquisition and brand harvesting.
5 Assessment Areas
What a PMax Audit Covers
Conversion Signals — Is the Algorithm Learning Correctly?
viaCMO checks: primary conversion action type, conversion counting method, signal volume against the 15-conversion threshold (adjusted from the standard 30 for PMax-heavy accounts), and whether optimisation signals conflict with the campaign's stated objective.
See the full conversion signals and tracking integrity audit for what's checked at the account level.
Budget Stability — Is Spend Consistent or Erratic?
viaCMO checks 90-day spend variance. High variance on a mature campaign is a flag, not a failure — but it warrants investigation.
Asset Group Quality — Is Creative Working?
viaCMO checks: asset group rating, image and video asset coverage, headline and description variant count, and call-to-action consistency.
Brand Cannibalisation Risk
viaCMO checks: whether branded terms appear in the Search Insights for PMax, whether a separate branded Search campaign exists, and whether campaign priority settings are configured to prevent cannibalisation.
Scaling Efficiency — Is PMax Generating New Demand?
viaCMO checks the proxy signals: audience signal coverage, new customer acquisition goals (where configured), and whether PMax spend is growing proportionally to overall account conversion growth.
Limitations
What viaCMO Can and Cannot Assess in PMax
Can assess
- Conversion signal integrity and volume
- Asset group quality ratings
- Budget variance patterns
- Brand cannibalisation signals via Search Insights
- Campaign-level CPA vs account benchmark
Cannot assess
- Individual placement performance — Google does not expose this
- Audience signal match rates — not surfaced in the API
- Channel-level spend breakdown (Search vs Display vs YouTube vs Shopping)
- Impression-level data — PMax does not provide it
- Incrementality — requires controlled holdout experiments
Where viaCMO cannot assess something, the audit says so. Stating limitations is the standard viaCMO holds its analysis to. The same discipline applies to the rest of the platform's full account audit.
FAQ
Frequently Asked Questions
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