Geo Experiment

Measured as

Measure Geo Experiment with a fixed attribution window, conversion event, and spend basis before comparing campaigns or creative tests.

Misused when

• Using too few regions (low power) and over-interpreting noise.
• Changing major campaigns mid-test (confounds).

Operator takeaway

• Use geo tests when user-level holdouts aren't feasible (e.g., offline or privacy constraints).
• Ensure regions are comparable and avoid cross-region spillover.
• Use Geo Experiment only inside a stable attribution rule, conversion definition, and time window so campaign comparisons stay honest.
• If performance changes, check whether the metric moved for a real business reason or because the measurement setup changed underneath you.

Next decision

• Quantify the impact with Incrementality Lift Calculator if you need to turn the definition into an operating assumption.
• Read Incrementality: how to tell if ads are actually driving growth if the decision depends on interpretation, policy, or trade-offs beyond the raw formula.