A geo lift experiment divides comparable regions into exposed and control groups to estimate media's additional effect. It can help when individual randomization is impractical or effects span channels.
In the demo, two regions track together before media starts, then one diverges. The target is that incremental difference, adjusted for pre-period behavior.
Check matching pre-trends and media spillover across regions. Few regions or major outside events increase uncertainty.
When to use
Use it to test cross-channel incremental sales at the regional level.