Advertising & Performance Practical insights
Measure what new customers cost in Performance Max
Evaluate Performance Max acquisition using a consistent new-customer definition, mature cohorts and incremental value instead of an isolated platform label.
A campaign report that labels someone new does not settle the business question: did the advertising create a valuable customer relationship? Google’s measurement guidance combines first-party data with causal evaluation. [1] Apply that distinction when assessing Performance Max acquisition, keeping platform classifications and your own customer records visible.
Define new before counting it
Agree whether new means first recorded purchase, first purchase within a period or first purchase in a particular brand. These definitions produce different totals. Document the available history and identity limitations. A guest checkout or a second email address can make an existing buyer appear new. Use the best permitted matching process and report uncertain cases separately rather than silently treating them as acquisitions.
Follow the cohort beyond checkout
Group customers by acquisition period and compare their net contribution over the same observation window. Include returns and variable service costs where material. For an illustrative subscription retailer, an introductory order may be unprofitable but later renewals could change the assessment. Keep observed renewals separate from forecast lifetime value, especially for the youngest cohorts.
Ask what would have happened anyway
Some first-time buyers would have arrived through existing demand. Where practical, use a properly designed holdout or geographic experiment to estimate additional customers. If that is not feasible, combine business trends and attribution evidence cautiously and describe the result as directional. A rise in platform-reported acquisitions alone does not establish incrementality.
Price the next increment of growth
Review the cost and contribution of additional spend rather than relying solely on an average across the whole campaign. Check whether expansion reaches different products, regions or customer types with weaker economics. Set the next budget step around a clearly stated hypothesis and review date. The decision is whether the next customers are worth acquiring at the expected cost, with identity and measurement uncertainty made explicit.
Sources and evidence
Sources checked on 4 October 2026. Proposed workflows and hypothetical examples are editorial analysis.