New Measurement Mistakes by Facebook

Facebook revealed faulty metrics with Instant Articles, its mobile publishing system, the fourth disclosure of a measurement error since September, according to Bloomberg. The admission sharpened calls for more independent organizations to monitor the performance of digital advertising. And some large firms that buy a lot of ads said they will more closely scrutinize their spending on the social networking giant and could shift marketing dollars elsewhere.

"People will take a step back and certainly look again where Facebook sits in their marketing mix," said Rob Norman, chief digital officer for ad buyer GroupM. "My sense is that a more pragmatic air will prevail," comparing the relationship between advertisers and the company to a marriage moving beyond the honeymoon stage.

In September, Facebook shared its first measurement error: inflated viewership numbers for its video ads, a relatively new product. Two months later, the company disclosed additional metric errors along with new tools for third-party measurement companies, including ComScore and Nielsen, to track its system more closely. Earlier this month, a report spotted a discrepancy between Facebook's internal metrics on how articles where shared and public measurements. Facebook confirmed the error.