Brief:

• Facebook, the social network with 6 million advertisers worldwide, offered credits to reimburse advertisers that were billed for mobile video ads that played on smartphones while out of view, Marketing Land reported. Facebook discovered two kinds of measurement errors during a regular review of its metrics and notified advertisers of the refunds last week.

• The first error let videos continue to play on Facebook's mobile website after a user swiped past them or switched to another tab in their device's browser. Videos hosted on Facebook, including ads, are supposed to stop playing when they are out of view.

• The second error let videos embedded in Facebook's mobile-only Instant Articles format continue to play while off-screen in its Android app. Slower download times may have led users to swipe past videos before they fully downloaded. Videos that took longer than one second to load would play even when they were no longer in view, per Marketing Land.

Insight:

Facebook has disclosed a dozen measurement errors since September 2016, some of which have led the platform to issue refunds. In this case, about 200 affected advertisers are receiving credits of more than $5,000, Marketing Land reported. The error was said to be much smaller than a glitch in Carousel ads running on Facebook's mobile website announced in May, which wasn't detected for a year and affected 0.04% of ad impressions, Facebook said.

It's also unlikely to have the reverberations of the initial discovery last fall that Facebook had considerably overinflated its video viewability metrics dating back to 2014 — an error that's spurred a lot of the discussion this year around the degradation of trust and lack of transparency with digital marketing channels. In the past, Facebook has been incredibly guarded about how it measures marketing efforts on its platforms, but repeated mistakes and growing pressure from some of the world's largest ad spenders, including Procter & Gamble, have led it to roll out new transparency initiatives in order to appease brands. 

It opened its ad metrics to an audit by the Media Rating Council to be completed by March 2019, Marketing Land reported in September. It's also this year greatly expanded partnerships with third-party firms like Moat and Integral Ad Science to verify ad measurements like viewability, which is the industry standard for video content. But each new disclosure of measurement errors undermines those positive steps.

The latest round is another reminder that marketers need to closely scrutinize how their ads are measured on digital media platforms such as Facebook, Google and Twitter. That's especially true as investigators continue to discover widespread ad fraud that scams millions of dollars from major brands. P&G, which spends an estimated $2.4 billion a year on advertising, in July reported cuts of approximately $100 million to $140 million in digital ad spend in 2Q 2017 because of brand safety concerns and ineffective ads online.