How can you have 0 impressions but a 100% completion rate?

Great question! Here's how it works:

Completion Rate is calculated using this formula:
(Player Completed Views ÷ Player Starts) × 100

This means completion rate is based only on how many times a video was started and how many times it was watched all the way through.

Impressions are not part of this calculation. So, it's possible to see 0 impressions but still have a 100% completion rate if, for example, someone started and completed the video multiple times without it registering as an impression (like in embedded players or testing environments).