Final answer:
A view-through conversion in a TrueView for Action ad occurs when a viewer sees an ad but doesn't click on it, but later completes a desired action related to the ad. This helps advertisers measure the effectiveness of their ads.
Step-by-step explanation:
A view-through conversion in a TrueView for Action ad occurs when a viewer sees an ad but doesn't click on it, but later completes a desired action related to the ad, such as making a purchase or filling out a form. This action is attributed to the ad even though there was no direct click. View-through conversions help advertisers measure the effectiveness of their ads in generating conversions without relying solely on click-through rates.