Facebook has found another bug in its ad-measurement systems — the fifth time in the last eight months the social giant has revealed an error in how it reports metrics.
The company said the impact of the recently discovered issue was minor, affecting only 0.04% of total billed ad impressions. “Regardless of how many impressions were affected, we take all bugs seriously and apologize for any inconvenience this has caused,” the company said in a blog post. Facebook said affected advertisers will receive a full credit for charges incurred because of the error.
According to Facebook, the bug misattributed clicks on video-carousel ads as link clicks (which advertisers pay for) when users were accessing the service using a mobile web browser on a smartphone. The error did not affect tabulations on desktop PCs or in the Facebook mobile app.
Facebook claims it’s trying to be as transparent as possible with advertisers, and the thinking is that such disclosures — however minor — will build trust with marketers. Earlier this year, the company also announced partnerships with more third-party measurement providers and expanded its relationship with Nielsen to verify its reporting.
Last September, Facebook revealed that it had overstated the average time spent viewing videos for two years. While that also didn’t affect ad rates, it gave marketers a skewed view of how well their ads were performing. That was followed by additional disclosures of measurement bugs, including one that overstated the “organic” audience of Facebook Pages.
The latest bug affected billing only for the video-carousel ad unit, and only when the advertiser chose to bid on link clicks. In addition, it only affected views for people who were on smartphone web browsers, according to Facebook. In those cases, advertisers were incorrectly billed when people clicked on the videos in the carousel to enlarge and watch them.
Facebook noted that most of its users — which numbered nearly 2 billion per month in the first quarter — access the service through its proprietary app for smartphone.