A brand notices their ads are getting impressions but wants to understand if customers are actually seeing them. Which measurement metric should they focus on?

Viewability measures whether served impressions had the opportunity to be seen. Impressions alone show that ads were rendered, but they do not confirm that the ad was actually in view. Amazon Ads uses viewability standards to distinguish viewable impressions from impressions that may have appeared outside the visible screen area. This makes viewability metrics the relevant measurement focus when visibility of delivered ads is the concern.