Facebook Concedes Measurement Errors…Again.
Oh dear Facebook executives, a few weeks after "videogate" you are admitting more measurement errors. Wasn't it enough to have GroupM call your artificially inflated video metrics "careless and unfortunate"? Well, yesterday Facebook admitted to the media buying community that it had uncovered a bug in a Page Insight dashboard that overstated the 7 day reach of a Facebook page by 49% and the 28-day reach by 122%. The paid reach has not been impacted by this measurement error. Below excerpts of the Facebook announcement.
"We've uncovered a bug in Page Insights. On one of our Pages dashboards, one summary number showing 7-day or 28-day organic page reach was miscalculated as a simple sum of daily reach instead of de-duplicating repeat visitors over those periods (see red circle in screenshot below). However, the vast majority of reach data in the Page Insights dashboard (marked green in screenshots below) was unaffected, including all the graphs, daily and historical reach, per-post reach, exported and API reach data, and all data on the Reach tab. The de-duplicated 7-day summary in the overview dashboard will be 33% lower on average and 28-day will be 55% lower; data in other fields is unaffected. This bug has been live since May; we will be fixing this in the next few weeks. It does not affect paid reach."
More here on Facebook's Update on Metrics and Reporting.