Less than three months after discovering an error in the way it reported video viewing numbers to advertisers, Facebook today revealed it has found several other mistakes in how it calculates marketing metrics.
The new errors affect how Facebook reported organic page reach over seven-day and 28-day periods, along with its metrics for completed video views, time spent by readers on Instant Articles and referrals for other apps and Web sites. Facebook noted today that the over-reporting and under-reporting errors do not affect how advertisers are billed.
In addition to working to correct the newly discovered errors, Facebook said it also plans several other changes to improve how it manages advertising metrics. Those changes include the possible addition of more third-party reviews of its reporting and the formation of a new Measurement Council of business and measurement executives.
Aiming for ‘Clarity and Confidence’
“We know having access to reliable metrics is critical to our partners who rely on Facebook to help grow their business,” vice president of advertising and global operations David Fischer wrote this morning on his Facebook page. He added that the updates announced today are designed to “give our partners more clarity and confidence about the insights we provide.”
One of the bugs Facebook expects to fix over the next few weeks involves how it calculated seven-day and 28-day organic page reach. Since May, the dashboard for those measurements has incorrectly based those numbers on a simple sum of daily reach, rather than eliminating the count of repeat visitors over those timeframes. After removing duplicate visitors, the adjusted page reach figures are expected to be 33 percent lower, on average, for the seven-day period, while the 28-day figures will average 55 percent lower.
Another error being corrected undercounted how many videos were viewed by Facebook users to completion. That problem, which resulted in an average undercount of 35 percent, stemmed from differences between video players and devices that can cause audio and video tracks to not be perfectly aligned.
New Channel for Metrics FYI
This summer, Facebook first announced it had discovered an error in how it calculated another metric on average duration of video viewing. That led to higher-than-actual measurement reports although, as with the new errors reported today, the mistake did not affect advertiser billing.
“While this is only one of the many metrics marketers look at, we take any mistake seriously,” Fischer noted in a post on the Facebook Business site in late September. “As soon as we discovered the discrepancy, we fixed it.”
In the wake of the latest metrics bugs, Facebook said it is launching a new channel for advertisers similar to the one it provides for updates about its News Feed feature. The new Metrics FYI blog will offer regular updates for marketers about changes and enhancements Facebook makes to its ad metrics.
