Which of the following is measured by Click-through Rate (CTR)?

Click-through Rate (CTR) is a key performance metric in digital advertising that measures the ratio of users who click on an advertisement compared to the number of times the ad is shown, known as impressions. Specifically, CTR is calculated by dividing the number of clicks on the ad by the total number of impressions, and it is usually expressed as a percentage.

This metric is vital for assessing the effectiveness of an ad in capturing user interest. A higher CTR indicates that a larger portion of users are engaging with the ad, suggesting that the ad is relevant and appealing to its target audience. Therefore, selecting the option that describes the relationship between clicks and ad impressions directly aligns with the definition of CTR. Understanding CTR helps advertisers gauge the performance of their campaigns and make data-driven optimizations.