Why Watch time is more important than views!
subversiveasset
Posting Mad!
Currently, we are indeed talking about watch time per video. The relationship between audience retention % (or average percentage viewed) and watch time per video is that audience retention is a percentage figure, whereas watch time is an absolute figure.
From my understanding, YouTube actually prioritizes watch time, not audience retention. So, audience retention is more of a "gut check" to see how users are liking your videos, but it's not directly important. For example, if you only had 20% retention, then you'd want to think about what is happening in your videos that is causing people to lose interest. However, the relationship between retention and watch time can produce some seemingly counterintuitive outcomes -- for example, if everything else was held constant, getting 20% audience retention on a 10 minute video is better than getting 100% audience retention on a 1 minute video, because in terms of watch time, that's 2 minutes of watch time vs 1 minute of watch time. (However, if there are two videos that are both 10 minutes, then one that has a higher retention will have a higher watch time than the other that has a lower retention.)
Ultimately, session watch time is even more preferred. So, if someone watches your 1 minute video, and then immediately watches another video, and then another (say, if all of those videos are in a playlist), then youtube imputes the session watch time somehow. (I'm not sure on the math of this, especially when it comes to videos by multiple people in the same playlist). This isn't discussed as much if only because it's not very easy to track.