Which of the below is NOT considered a conversion metric?

The correct answer is Impressions because impressions are not considered a conversion metric. Impressions simply track how many times an ad is displayed to a user, without indicating whether the user took a desired action, such as clicking or making a purchase. Conversion metrics, on the other hand, track actions that signify a successful outcome, such as purchases or completed sign-ups. Detail page views and purchases are examples of conversion metrics because they represent user interactions that move them closer to achieving a campaign's goals. Impressions, while important for measuring ad visibility, do not directly measure conversion outcomes.