Brand lift
Brand lift measures the change a campaign caused in awareness, recall or purchase intent, typically via exposed-versus-control surveys. It answers what reach metrics cannot: whether anyone remembered. Sample sizes make it a tool for larger campaigns; small ones proxy it with branded-search volume and direct-traffic movement over the campaign window.
Worked example
Exposed audiences show 24% unaided recall against 17% control — a 7-point lift attributable to the campaign.
Related: Share of voice · CPM
Full context in the guides, or measure it yourself with the free tools.