VTR

VTR measures what percentage of people who saw a video ad started watching it, most commonly used for YouTube TrueView campaigns.

VTR is specific to skippable video ad formats. It's essentially asking "of everyone who had the chance to skip this in the first 5 seconds, how many chose to keep watching instead." It's a strong, fast read on hook and relevance quality, arguably a cleaner signal than thumbstop rate because the viewer has actively chosen not to skip, rather than just failing to scroll past.