Facebook and Instagram Video Ad Metrics: Reading the Quartiles
"The video underperformed" is not a diagnosis. Video completion data turns it into one, and it is one of the least-used parts of Meta reporting.
What Meta reports
For every video ad: plays, thru-plays, and the number of people who reached 25%, 50%, 75%, 95% and 100% of the run time, plus average watch time.
Plotted, those five points form a drop-off curve. Where the curve falls tells you which part of the creative failed.
The three shapes, and what each means
Heavy drop before 25%. The hook does not work. Most people never saw anything after the first few seconds, so nothing after the first few seconds is worth changing. Test openings - a different first frame, a different first line, starting closer to the point.
Holds to 25, collapses by 50. The hook works, and the middle does not deliver on the promise it made. This is usually a pacing problem or a bait-and-switch: the opening implied one thing and the body is about something else.
Holds to 75, dies before 100. The content is working. What fails is the end - the offer, the call to action, or simply that the video is longer than it needs to be. Try cutting the last 20% entirely and see whether completions and conversions rise together.
Thru-plays versus completions
A thru-play is 15 seconds, or the full video if shorter. It is a billing and optimisation unit, not a measure of whether anyone watched to the end.
For a 12-second ad, thru-play equals completion. For a 90-second ad, a thru-play means someone watched a sixth of it. Reporting thru-plays on long creative overstates performance considerably, and it is an easy mistake to make because the number is prominent.
Average watch time is the sanity check
Two videos can show the same 50% completion rate with very different average watch times. A low average with a decent completion rate usually means a bimodal audience - a small group watched it all, most left almost immediately. That is often an audience problem rather than a creative one, and the quartile curve alone will not reveal it.
Why this needs history
Creative fatigue shows up in the quartile curve before it shows up in cost per result.
A creative that held 40% to the halfway mark in April and holds 22% in August is dying, and the CPL may not have moved yet because the algorithm is compensating elsewhere. If your reporting only retains a rolling window, you cannot see that trend and you find out when the cost moves, which is later and more expensive.
Inflowave stores all five completion points plus average watch time per ad per day, retained, so the curve is comparable across months. The full metric set is covered in the 58-metric guide.
What to report to a client
Not five percentages. One sentence: "the hook is working, the middle isn't - we're recutting the section after the first five seconds," backed by the curve. The numbers are the evidence, not the report.
