Note: Metrics shown in this section are derived from post level lifetime values for content posted within the selected period. 

Likes: Total likes including likes on shares. 

Comments: Total comments including comments on shares. 

Shares: Total shares including shares on shares. 

Impressions: The total number of times users saw your posts. 

Interactions: The total number of likes, comments and shares (including interactions received on shares). 

Engagement: The total number of times people likes, commented, shared or clicked on your posts.

Clicks: includes, click to play, photo view and other clicks

For more information on Facebook metrics, please refer to the following FB developer resource: https://developers.facebook.com/docs/graph-api/reference/v20.0/insights