Why It's Important
Engagement rate measures your effectiveness at engaging your audience using Facebook Page Insights, the data Facebook provides about your Page’s performance.
The engagement rate metric is designed to show you the number of unique users who engaged with your content as a percentage of the number of users who were exposed to it.
How to Use It
Facebook Insights data provides in-depth unique user totals for engagement actions on your posts, as well as the overall reach of your posts.
Over time, how your engagement rate fluctuates and varies by post type can tell you a lot about which content is successful for your brand and appealing to your fans.