Last-click attribution lies. Platform ROAS is inflated. The only way to know what advertising is truly driving is incrementality testing. We design and run holdout tests, geo experiments and conversion lift studies that give you the ground truth on every channel.
Incrementality testing measures the causal impact of advertising by comparing what happened with advertising versus what would have happened without it. It answers: would this customer have converted anyway?
Attribution (even MTA) shows correlation, not causation. High platform ROAS often includes customers who would have purchased organically. Incrementality testing reveals true additionality.
We identify comparable geographic markets, run advertising in the test markets while withholding it in control markets, then measure the revenue difference — attributing the gap to the advertising.
Meaningful incrementality tests typically run for 4–8 weeks to account for purchase cycle variation and build statistical significance.
Most brands find 20–50% of attributed conversions are not truly incremental — they would have happened anyway. This insight allows significant budget reallocation to higher-incrementality channels.
Book a free measurement consultation and design your first incrementality test.