Video Completion Rate
BeginnerVideo completion rate is the share of plays that ran to the end of the video, out of all plays that started.
It is measured with milestone events: a play start followed by crossings of the 25, 50, 75 and 100 percent marks, with the completion rate being the ratio of the final milestone to the start. Two choices move the number dramatically: autoplay fills the denominator with plays nobody intended, pushing the rate down, and counting a seek as a milestone crossing pushes it falsely up. More importantly the rate depends heavily on video length, so comparing a thirty-second clip with a ten-minute tutorial is meaningless, and the drop-off curve across milestones usually says more than the final figure because it shows exactly where people left.
How it is calculated
Video completion rate = plays that reached the end ÷ plays that started
The denominator is the play-start event, and autoplay should be reported separately or two different behaviours end up mixed in one number. The numerator is the hundred-percent milestone, so closing the page in the final second does not count as completion. The output is a percentage, and the counting basis can be plays or distinct users as long as that choice stays fixed in the metric definition.