Incremental lift asks what changed beyond outcomes that would have happened without advertising. Randomized exposed and control groups provide a basis for estimating that counterfactual.
In the demo, purchase rates start together and diverge; only the gap is highlighted. The example values illustrate the concept, not a campaign result.
Selection bias, outside exposure, and small samples can distort estimates. Inspect experiment design and uncertainty before acting.
When to use
Use it to test whether media caused additional purchases.