The ratio of users who click on a specific call-to-action (e.g., email link, push notification, paywall button) versus those who viewed it. CTR is a key engagement metric for evaluating creative performance and funnel effectiveness. Click-through-rate originated in the email and banner ad world, where everything was on a desktop. With mobile, some companies now call this same metric tap-through-rate since people are tapping on their phone vs clicking on desktop, but at the end of the day it's really the same type of measurement.
