Metrics
Click-through rate (CTR)
Also called: CTR
The percentage of people who click after seeing your thumbnail or title — the gate to every other metric.
Click-through rate is the share of impressions that turn into clicks. On YouTube it is driven by the thumbnail and title; on feed-based platforms the cover frame and first caption line play the same role. No matter how good the video is, a low CTR caps how many people ever start it.
Improving CTR is mostly a packaging problem: a clear, curiosity-driving title and a high-contrast cover with a single focal point. Testing two or three titles or covers on the same clip is the fastest way to find what your audience clicks.