Facebook angers ad buyers over viewing time miscalculation

Facebook has attracted the wrath of advertising buyers and marketers after overestimating the average viewing time spent on the platform for two years running, according to a report in the Wall Street Journal.

Facebook revealed a number of weeks ago on its advertising help centre that the metric it used to calculate average viewing time only included videos that were watched for more than three seconds, leading to the average time being artificially inflated. The social network said it was introducing a new metric to calculate viewing time more accurately by counting all video viewing time.

According to the Journal, ad agency executives have since investigated the change made by Facebook and forced the company to give a more detailed account of its practices. It said that Publicis Media had informed advertisers in August that the metric used had exaggerated average viewing time by between 60% and 80%.

According to the Wall Street Journal, Publicis’s letter said that Facebook’s introduction of a new metric was designed to cover up the company’s earlier mistakes. It said that the revelation that Facebook had been exaggerating viewing time highlighted the need for third-party verification of data.