Which metric is commonly used to measure the effectiveness of an online ad campaign?

Click-through rate (CTR) is a widely used metric in digital advertising that measures the effectiveness of an online ad campaign by indicating how often people click on an ad after seeing it. Specifically, CTR is calculated by dividing the number of clicks an ad receives by the number of impressions (the number of times the ad is shown). A higher CTR suggests that the ad is resonating with its audience and enticing them to engage, signifying successful targeting and creative execution.

Measuring the effectiveness of a campaign through CTR helps advertisers understand how well their ads are performing and can provide insights into whether the ad’s messaging, placement, and design are appealing to the target demographic. While metrics like CPC and ROI are important for assessing costs and overall profitability, and impression rate highlights visibility, it is the CTR that specifically reflects the level of user engagement with the advertisement itself, making it a critical measure for evaluating the campaign's immediate effectiveness in attracting interest.