In a scenario where a user clicks on an ad on day four, which impression receives conversion credit?

The correct answer is that the ad clicked on day four receives conversion credit. This is because conversion credit is usually attributed to the most recent customer interaction that led to the conversion, which in this case is defined as the click on the ad.

In programmatic advertising, marketers analyze user interactions and behaviors leading up to a conversion to assess the effectiveness of their campaigns. When a user clicks on an ad, that action is recognized as the direct engagement that prompted the conversion event, such as making a purchase or signing up for a service. Therefore, the click event holds the most significance for attribution purposes and is awarded conversion credit due to its role as the last point of engagement before the conversion.

The impressions viewed on previous days serve as part of the user's journey and may contribute to the overall effectiveness of the campaign, but they don’t directly receive conversion credit because they did not directly lead to the conversion action. This perspective aligns with common attribution models that prioritize last-click attribution, which is a frequent practice in digital advertising analytics.