Facebook Insights notes/limitations

Historical limitations: Facebook Insights’ API will not retain any data older than 2 years, as stated at the top of their technical documentation here: https://developers.facebook.com/docs/graph-api/reference/v4.0/insights. Therefore, if you go back further than 2 years in the past in your dashboard, your widgets will not show any data.
Page VS post metrics: some metrics can be used both without a dimension ("page"-related metric) or with a dimension ("post"-related metric).
- The metrics for the page may report different data: it will include actions on the page, whether or not it is on a post published during the period you are looking at.

- The metrics for the post will include reactions on a given post and be reported only in the period where the post has been published.
  - ex: 5 likes on a post in June, 4 likes on a post in May (all likes executed during the month of June) will be reported as 9 likes for the page. However, only the June post will show likes as the post in May will be reported for, in May.

Demographic dimensions limitations: Due to the particularity of Facebook Insights’ API, demographic dimensions such as City and Country, will only be returned if there is data for 100 or more people.
Non-video posts, in widgets containing video-related metrics (e.g, Video Views, 30-second Video Views) will display 0 for these metrics. Data for other non-video metrics will be fetched correctly by the widget.
At this time, posts with attachments will be filtered out of the results which may cause some discrepancies.
Update (September 2025): All videos on Facebook are now Reels. All videos posted to Facebook will be shared as reels, regardless of length or orientation. This unifies the video experience for creators and viewers. Learn more about this change.