How we aggregate the data
The data reported by our site are extracted from Facebook’s Ads Library API. The Ads Library reports spend per ad in ranges only, with a geographic and demographic distribution of that spend.
We calculate spend estimates per page per day by attributing an ad’s spend to the day it started running, with an estimated spend of the midpoint of the range reported by Facebook. The spend on all ads for a page that began running on a particular day are summed to create that advertiser’s spend estimate for the day.
We calculate demographic and geographic spend estimates for each ad by applying an ad’s demographic or geographic distribution to our spend estimate for the ad. A page’s daily spend on a particular demographic or geographic group is estimated by summing the spend for that group on all ads run by that page on that day.