Hook Rate (Thumb-Stop Ratio)

What is Hook Rate?

Hook rate (also called the thumb-stop ratio) is 3-second video views divided by impressions, and it is the algorithm’s first relevance signal, the single biggest predictor of whether a creative earns cheap distribution or gets throttled.

The formula and a worked example

Hook rate = 3-second video views ÷ impressions. It measures one thing precisely: did the opening frames stop the scroll? Work an example with round, illustrative numbers. A video served 100,000 impressions that earns 30,000 three-second views has a 30% hook rate. Because the platform reads that as relevance, a stronger hook lowers CPM and widens delivery, so a 30% hook can end up costing far less per result than a 20% one on the same audience, before the landing page or offer even enters the picture.

The working bands on Meta

These are directional bands, not laws, but they make hook rate a fast pass-or-fail on a new variant long before enough conversions accumulate to judge CAC.

The earliest fatigue alarm you have

Hook rate is also the earliest warning of creative fatigue. Across AdBoost Health partner accounts, fatigue surfaces in CPM and hook rate before ROAS ever moves, because viewers who have already seen the opening three seconds scroll straight past. Illustratively, a hair-loss video sliding from a 32% to a 24% hook rate on an unchanged audience is a rotate-now signal weeks before the CAC damage lands, and waiting for ROAS to confirm it means paying the fatigue tax in full. Monitor hook rate against your own trailing baseline so a rotation still fixes the problem cheaply.

Why it matters for health and DTC brands

Health creative is a volume discipline, because only about 1 in 8 health creatives becomes a durable winner, so hook rate is the fastest early filter for deciding which of a month’s 15–25 test variants deserve real budget. Kill the low-hook variants early, and concentrate spend and iteration on the ones that stop the scroll. Because every replacement ad must also clear claims review before it can run, the refresh pipeline has to stay ahead of the decay, which makes hook rate a creative testing instrument, not a vanity stat. Read it alongside outbound CTR (the roughly 1.2% cold-traffic bar), CPM, and eventually CAC, since a great hook that never converts downstream is still a losing ad. The goal is a pipeline of scroll-stoppers, not one hero video.

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