You measure upper funnel ads impact on DTC revenue by tracking downstream lift in branded search, direct traffic, and conversion rate over time, rather than relying on last-click attribution, which almost never credits an awareness campaign for the sale it eventually influenced. Upper funnel channels like video, social awareness campaigns, and display are designed to introduce a brand, not close a sale in the same session, so measuring them the same way you measure a retargeting ad produces a misleadingly low number.