CTR (click-through rate)

CTR measures how compelling an ad or listing is to the people who see it, which makes it a creative and relevance signal rather than a business outcome. In search and social advertising it also feeds quality and ranking systems that reward more engaging ads.

A high CTR is only valuable if the traffic converts; clicks from a misleading ad inflate CTR while wasting spend. Read CTR as a measure of attention earned, then follow it with conversion rate to see whether that attention was worth anything.