A natural products advertiser that sells beauty items is about to launch a new product for skin hydration. Its main key performance indicator (KPI) is to understand how many unique people are seeing its ad. Which metric is most aligned to its KPI?

The metric most aligned with understanding how many unique people have seen an ad is Reach. While several metrics track visibility, they serve different functions in campaign analysis:Reach: Measures the number of unique individuals (or accounts) who saw your ad at least once. This directly answers the advertiser's KPI of understanding the breadth of their audience.Impressions: Tracks the total number of times your ad was displayed. If one person sees your skin hydration ad three times, it counts as 1 for Reach but 3 for Impressions.Frequency: Indicates the average number of times each unique person saw your ad. It is used to monitor "ad fatigue" rather than unique audience size.Video views: Counts the number of times people watched your video (usually for a specific duration, like 2 seconds). This measures engagement or interest rather than the total unique audience exposed to the content.