Facebook overestimated the average amount of time that people spent watching videos on its platform for two years, according to reports.
Several weeks ago Facebook quietly disclosed that its metric for the average time users spent watching videos was inflated because it was only factoring in video views of more than three seconds.
The Wall Street Journal, which broke the story, said the earlier counting method likely overestimated average time spent watching videos by between 60% and 80%.
Facebook said it was introducing a new metric to fix the problem, but the news has already upset big ad buyers, the WSJ states.
In a statement, Facebook said: “We recently discovered an error in the way we calculate one of our video metrics. This error has been fixed, it did not impact billing, and we have notified our partners both through our product dashboards and via sales and publisher outreach.
“We also renamed the metric to make it clearer what we measure. This metric is one of many our partners use to assess their video campaigns.”
The news will be embarrassing for Facebook, which has defined its future in video. It is also like to increase friction between more traditional media such as TV which offers advertisers transparent and independently verified metrics.
Earlier this year, the IPA’s research director called for more transparency from the likes of Google and Facebook over their handling of audience measurement figures.
Speaking at the Future of Media Research conference in February, Lynne Robinson said tech firms operating in media markets must be more open about how they constructed their datasets.
“They only give a partial view of the market, and it is not often clear how something has been calculated,” she warned. “If they are comparing their data to other media datasets, how have they calculated that impact?
“We need far more transparency.”
