If you optimize for ThruPlay, this is a great custom metric to create to measure the quality of video views.
By optimizing for ThruPlay, you’re going to get a lot of The number of times your video was played for at least 15 seconds or to completion. More (that’s how it works!). But this can be misleading.
What percentage of those ThruPlays watched to completion? Obviously, it will be a lot for shorter videos, but not for longer ones.
With this Advertisers can create custom metrics that combine existing metrics with a mathematical formula. That formula can be based on Meta's current ads metrics, standard events, custom events, and custom conversions. More, you will divide the number of 95% View by ThruPlay. Then add the metric as a column and save those columns for access later.
Compare videos that are a similar length since you’re bound to have higher percentages for short videos than longer ones. And feel free to experiment with other ratios related to watch time as well.
Hope this helps!