Skip to main content

Video completion metrics explained

When a video ad plays, four standard milestones are tracked: First Quartile (25% watched), Midpoint (50%), Third Quartile (75%), and Completes (100%). These are reported as raw counts in your reports — the number of ad plays that reached each point. Together they form a completion funnel that shows both how engaged your audience is with video ads and how attractive your video inventory is to buyers.

Why completion rates are a commercial signal​

Video buyers use completion rates as a proxy for audience engagement and placement quality. A publisher whose inventory delivers strong completion rates will attract stronger bids and better-paying campaigns, because the advertisers' messages are actually being received. For video eCPM, completion rates are often as important as viewability.

Reading the funnel​

A healthy completion funnel drops gradually from First Quartile to Completes, with no steep drop between any two milestones. Here is how to interpret what you see:

  • First Quartile is high but Midpoint drops sharply — viewers are losing interest in the first half. Often because the creative is too long or the placement feels intrusive.
  • Midpoint is strong but Third Quartile drops — viewers are engaged but abandoning before the end. Common with longer ad formats.
  • Completion rate is strong across all milestones — a well-placed creative with an engaged audience. This is the profile that attracts premium video demand.
Example

These are illustrative figures only — actual rates vary by publisher, format, and audience. Out of 10,000 video ad starts, a healthy funnel might look like: First Quartile = 8,000 (80%), Midpoint = 6,500 (65%), Third Quartile = 5,000 (50%), Completes = 4,000 (40%). A steep drop at Midpoint — say, falling to 30% from 80% at First Quartile — would suggest an issue worth investigating.

Instream vs Outstream completion rates​

Instream video (pre/mid/post-roll within video content) naturally achieves higher completion rates than Outstream (autoplay in editorial content). Instream viewers are already in a video-watching mindset. This is one reason Instream commands higher eCPMs.

Use the Product dimension in the Reports page to compare Instream and Outstream completion rates on your inventory.

Practical tips
  • If completion rates have dropped without a change in your ad setup, check whether your demand partners have changed the creative length mix running on your inventory — longer ads have structurally lower completion rates.
  • Adding Device as a second dimension in your video reports will often reveal differences between mobile and desktop completion rates, which can point to placement or loading speed issues on a specific device type.

See also: Video ad products explained · What is viewability and why does it matter?