Facebook has promised to compensate select advertisers with one-time “credits” after admitting to a technical glitch in its Conversion Lift tool that went unnoticed for more than a year.
According to AdExchanger, which was the first to report the issue, Facebook contacted advertisers and media agencies earlier this month to warn them of the mistake, which was fixed back in September.
The company said that a coding error caused its Conversion Lift tool to undercount the number of people who had been served ads from August 15, 2019 to August 31, 2020.
And, consequently, it would offer credits to some advertisers who used the tool over the period, but only for those who were “meaningfully affected” and on a case-by-case basis.
The scale of the problem is unknown, but it is thought to have affected thousands of advertisers around the world and follows other incidents when Facebook supplied inaccurate data to its clients.
For example, it was discovered in 2016 that Facebook had vastly overestimated average viewing time for video ads on its platform for two years, causing advertisers to overspend.
Advertisers are expected to stick with Facebook, despite the latest error, but the revelation has prompted disquiet among several agencies and their clients.
“More so than past measurement problems with Facebook’s ad platform, this error has the potential to be extremely serious,” one large buying agency advised its clients in a memo seen by the Wall Street Journal.
“The fact that it led to a systematic overstatement of ad performance, combined with the year-long duration of the error, likely misinformed media budget allocations. These misallocations came at the expense of both advertiser media efficiency and Facebook’s competitors,” the memo added.
Florian Adamski, CEO of OMD Worldwide, agreed “this is not an easy fix”. “It’s not like, pay a couple thousand or million bucks and it’s over. This goes a lot deeper and we need to find out how to rectify the damage done and make sure it doesn’t happen again,” he said.
“This can’t just be covered with a one-time compensation in credits. It needs that reconciliation for every single client on how did it influence the investment decisions we made.”
Sourced from AdExchanger, Wall Street Journal; additional content from WARC