Data & Analytics Practical insights
Plan your first Meridian GeoX marketing experiment
Design a useful geo-experiment with Meridian GeoX by defining the budget decision, comparable markets, measurement period and sources of contamination.
Google announced global general availability of Meridian GeoX in September 2026. [1] Its availability makes geo-experimentation more accessible, but the software cannot rescue an experiment that asks an unclear business question. Begin with the decision you will make after the results arrive.
Specify the treatment and outcome
For example, a retailer could test whether additional paid video spending increases completed orders in selected markets. Define the incremental spend, eligible geography, outcome source and observation period before launch. Separate orders from attributed platform conversions. Decide whether the outcome is revenue, contribution margin or customer acquisition; changing that choice after seeing results invites selective interpretation.
Check whether markets are usable
Collect consistent historical outcomes and media activity by geography. Examine seasonality, distribution differences, unusually large markets and planned local promotions. A comparison market with a store closure may be unsuitable even when its historic sales resemble a treatment market. Use the documented design tools and statistical expertise to assess detectable effects, not a universal minimum number of weeks.
Protect the contrast
GeoX supports different experimental designs, including holdback and increased-spend approaches. [2] Choose one compatible with your business constraints. Check whether advertising, customers or offers spill across boundaries. Record national campaigns and other interventions that could dilute the difference. Preserve the agreed allocation and log operational deviations instead of retroactively redefining which markets count.
Turn the estimate into a decision
Review the estimated effect with its uncertainty, implementation fidelity and financial consequences. An inconclusive test may mean the proposed effect was too small to resolve; it does not prove zero impact. Treat any result as evidence for the tested markets, spend levels and period. Before launch, write down what evidence would justify scaling, repeating or stopping the intervention, and have the measurement owner approve that plan.
Sources and evidence
Sources checked on 4 October 2026. Proposed workflows and hypothetical examples are editorial analysis.
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