Incrementality

Incrementality is the measure of outcomes (conversions, revenue, sign-ups) that happened because of marketing and would not have occurred otherwise. It is established with controlled experiments — most commonly geo lift tests or holdout/control groups — that compare an exposed group against an unexposed one to isolate causal lift rather than correlated touchpoints. As user-level tracking weakens, incrementality testing has become a primary way to validate channel value and calibrate models, answering which results did this spend actually cause?

Source: business.google.com