Facebook to repay advertisers after miscalculating metrics

Facebook is compensating select advertisers after discovering a year-long error in its conversion-data reporting, an issue that is believed to have impacted thousands of advertisers globally.

A code error that affected Facebook's free Conversion Lift tool caused the platform to undercount the number of sales from people who were exposed to ads on Facebook apps for an entire year, from August 2019 to August 2020.

Facebook alerted advertisers and media-buying agencies to the issue earlier this month. The issue was first reported by AdExchanger.

A Facebook spokesperson said in a statement: "While making improvements to our measurement products, we found a technical issue that impacted some conversion lift tests. We've fixed this and are working with advertisers that have impacted studies."

The social-media network is offering one-time credit to advertisers who were "meaningfully affected" by the issue. It will assess the impact to advertisers on a case-by-case basis depending on how they used this product.

Facebook claims that a "small number" of advertisers were impacted by the misreported metrics. But major advertising agencies have said that several of their clients have been affected.

This is not the first time Facebook has admitted to an error in its advertising metrics. In 2016, it was discovered that the tech giant had vastly overstated video advertising metrics for two years, causing advertisers to overspend. A lawsuit filed in 2018 alleged that Facebook knew about the inflated metrics for more than a year before it alerted advertisers.