What is incrementality in marketing?
Incrementality is the extra business outcome, such as sales, sign-ups or visits, that happened because of an ad campaign and would not have happened without it. It is measured by comparing a group exposed to ads with a similar control group that was not. It separates true impact from conversions that would have occurred anyway.
Attribution reports can credit ads for purchases people were going to make regardless, such as branded search clicks by loyal customers. Incrementality tests fix this with a holdout group: randomly withhold ads from some users or regions, then compare outcomes. The difference is the incremental lift.
Forms include user-level lift study tests run by platforms, geo experiments that switch media on or off by region, and ghost-ad methods. Results feed marketing mix modeling calibration. Fraud distorts incrementality too: Attribution fraud such as click injection claims credit for non-incremental conversions.