Retargeting naturally focuses on users who already know a product or app. That makes attribution especially important because some users may have returned even without seeing an ad. Incrementality provides a way to ask a more useful question: how many outcomes were actually caused by the campaign?
Attribution and incrementality answer different questions
Attribution identifies which touchpoint receives credit for a conversion under a defined rule. Incrementality looks at the additional behavior generated by advertising compared with what would likely have happened without the campaign. Both views can be useful, but they should not be treated as identical.
Audience recency matters
A user who was active yesterday may have a high natural probability of returning. A user who has been inactive for several weeks may represent a different opportunity. Retargeting strategies can therefore use inactivity windows, audience segments and frequency controls to reduce spend on users who are already likely to convert organically.
Use testing to improve budget decisions
Holdout groups and other controlled experiments can help advertisers estimate incremental lift. The results can then inform bidding, audience definitions and budget allocation. Over time, the campaign can focus more on segments where advertising creates measurable additional value.
For performance teams, incrementality does not replace ROAS or attribution reporting. It adds another layer of evidence that helps explain whether retargeting is genuinely changing user behavior.