Youtube has recently updated the way it counts a “view”, reducing the watch time from 30 seconds to 10 seconds.

As per YouTube:

“Our system will now count an ‘Engagement’ whenever a user clicks or watches 10 seconds or more of your TrueView for action ad using maximize conversions or target CPA bidding.”

Note: the change in measurement is only for TrueView for action ads and will not alter YouTube’s overall view count metrics in general reporting. But for advertisers paying for such engagements, the calculations will be different.

Read more here.