Note: Metrics shown in this section are derived from post level lifetime values for content posted within the selected period.
Video Views: The total number of times your Page’s videos were viewed for 3 seconds or more.
Engagement Rate: The number of unique users who liked, clicked, commented, or shared the post divided by the post reach.
Video Reach: The number of unique people who saw your Page’s video posts.
Video Plays: The total number of times your Page’s videos were clicked to play for more than 3 seconds.
For more information on Facebook metrics, please refer to the following FB developer resource: https://developers.facebook.com/docs/graph-api/reference/v2.8/insights