Incrementality

Incrementality answers the question: "Would this conversion have happened anyway without this ad?" It's the gold standard for measuring true marketing effectiveness, but it's also the hardest to measure. Unlike attribution, which assigns credit based on touchpoints, incrementality focuses on causality. A conversion might be attributed to a Facebook ad, but if the customer would have bought anyway (perhaps through branded search), that ad had zero incrementality. Measuring incrementality requires controlled experiments like holdout tests, geo-experiments, or conversion lift studies. These tests compare conversion rates between a group exposed to ads and a control group not exposed. The difference represents true incremental impact. This is why sophisticated brands are moving beyond attribution toward incrementality measurement.