Which of the following is a common key performance indicator (KPI) in digital marketing?

Click-through rate (CTR) is widely recognized as a key performance indicator (KPI) in digital marketing due to its direct relationship with the effectiveness of online advertising campaigns. CTR measures the percentage of users who click on an ad after seeing it, which helps marketers assess how well their ad copy, visuals, and targeting strategies resonate with the audience.

A high CTR indicates that an ad is successfully engaging users and encouraging them to take the desired action, which is crucial for optimizing marketing efforts and maximizing return on investment (ROI). Therefore, CTR plays an essential role in evaluating the performance of various digital marketing channels, such as display ads, email campaigns, and social media promotions.

In contrast, while the brand loyalty index and customer satisfaction score are important metrics for understanding customer relationships and product performance, they do not directly measure the effectiveness of specific digital marketing initiatives. Employee turnover rate is primarily a human resources metric and does not pertain to marketing performance.