Hook rate is a derived metric. Meta does not report it under that name; advertisers calculate it from two numbers Meta does report. The numerator is 3-second video plays, which Meta defines as the number of times a video played for at least 3 seconds, or for nearly its whole length if shorter, counted once per impression with replays excluded (Meta). The denominator is impressions.
Hook rate = 3-second video plays divided by impressions.
A related metric is hold rate, usually ThruPlays divided by 3-second plays. Meta counts a ThruPlay when a video is played to completion or for at least 15 seconds (Meta). Hook rate asks whether the opening works; hold rate asks whether the rest does.
Example. An ad gets 40,000 impressions and 11,200 3-second plays, a hook rate of 28 %. Of those, 3,360 become ThruPlays, a hold rate of 30 %. A second ad with the same body and a new opening gets 14,800 3-second plays on the same impressions, a 37 % hook rate. The brand moves budget to the second ad. Example numbers, not a benchmark.
When brands use it. The pain this answers: “We paid $300 a video and nine out of ten never beat our control.” Hook rate is the first filter in creative testing. It is cheap to measure, shows up within a day of launch, and isolates the opening from everything else. Brands running creator videos as partnership ads compare hook rates across creators to decide which videos deserve budget.
The creator’s view. Hook rate is the metric a creator can most directly influence, and the one a brand on a share of ad spend will quote when deciding whether to keep spending on a video. Asking for the hook rate of your videos is a reasonable request after a test.