Facebook has reported yet another glitch in the data it gives publishers and marketers to understand their activity on the social network.
This time Facebook found a problem that gave some publishers inaccurate traffic numbers, underestimating iPhone audiences on certain posts, according to a blog post from Facebook on Friday.
"We've uncovered an issue for a small group of Instant Articles publishers that impacts reporting in comScore," the blog post said. "ComScore alerted us to the issue, and we've since identified this is a result of a recent Facebook update that impacted."
Instant Articles are multimedia posts that publishers use to give readers a faster experience because they load quickly. The trade-off is that readers get the full stories without leaving Facebook and visiting publishers' sites.
Publishers can sell ads into Instant Articles, though, and often rely on the traffic numbers in talks and deals with advertisers. ComScore does help verify those numbers.
"We have fixed the issue and are working with comScore to produce updated estimates for the relevant time periods for the small group of partners affected," the blog post said. "We have reached out to affected publishers."
One publishing executive said the Instant Articles mistakes were negligible, because publishers can use third-party technology to measure traffic within those kinds of posts. Still, in general, any faulty reporting on Facebook pages can mess with a publisher's strategy, the exec said.
"It does really stink that so much stuff may be wrong," the exec said. "We made a lot of bets, investments, based on what we thought the audience clicked on most on our pages. Now, all that may be skewed."
There wasn't any existential damage for the publisher, but the importance of sound data is clear -- these numbers are used to plan what type of content to produce, what plays best with audiences, and they can affect dramatic changes in programming.
The Washington Post announced that the error depressed its traffic for months, and expected that it kept the publication from reaching a symbolic milestone -- 100 million unique visitors. The Washington Post said it had 99.1 million visitors in November but believed that figure would top 100 million once the Facebook glitch was accounted for. It also likely topped that amount in October for the first time in its history, the Post said.
It was the fourth time in recent weeks that Facebook revealed reporting errors. In the first such case, Facebook told advertisers and brands that its average video view stats were faulty. Facebook also previously supplied other faulty metrics on Instant Articles, overstating how long people spent inside the posts.
Most of Madison Avenue think Facebook has acted in good faith and the glitches are simply sloppy mistakes, the result of moving fast to create a marketing platform and supply robust reporting.
Still, agencies are in the position of having to calm concerned clients.
Facebook is not alone in supplying data on itself to brands, and rivals also are scrutinized over their metrics. Facebook is the most high-profile, however.
Facebook has started to open up the platform to third parties like Integral Ad Science and Moat to give more independent assessments of its reporting.
The move toward transparency is a start, but many advertisers are still interested in even more data and verification tools.
