Incrementality

Incrementality tests causal lift: holdout geographies, audience splits, or campaign blackouts revealing which “attributed” conversions were genuinely created versus merely claimed.

Why it matters specially here

Gambling’s attribution surface invites claiming — brand bidding, retargeting and last-click interceptors all book conversions with debatable causation. Incrementality testing prices them honestly: pausing brand-term affiliate coverage in a test GEO, measuring registration deltas, and negotiating from evidence. It’s methodologically demanding (power, contamination, seasonality) and politically explosive (channels rarely welcome causal audits of their claimed value) — which is precisely why the operators that run it quietly outspend competitors where it works and cut where it doesn’t.