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.