Facebook, on Friday, said it has rectified an error in the way it calculated average duration of video viewed, one of the metrics available to marketers to gauge the efficacy of their video campaigns. The Wall Street Journal reports that this miscalculation was going on for two years.
According to Facebook, it first noticed this error about a month ago. The social media giant said that instead of the metric reflecting total time spent watching a video divided by the total number of people who played the video, it reflected the total time spent watching a video divided by only the number of “views” of a video. Facebook classifies a "view" as when a video is seen for 3 seconds or more.
This discrepancy could potentially have led marketers to think that Facebook videos are performing better than competitors as views will necessarily be a subset of total number of video plays.
However, Facebook says that it has already fixed the error last month and informed partners while also updating its video metrics. It further stated that this miscalculation "has not and will not going forward have an impact on billing or how media mix models value their Facebook video investments."
In a post on the Facebook Blog, David Fischer, VP (Business and Marketing Partnerships) at Facebook wrote, "While this is only one of the many metrics marketers look at, we take any mistake seriously. As soon as we discovered the discrepancy, we fixed it. We informed our partners and made sure to put a notice in the product itself so that anyone who went into their dashboard could understand our error. We have also reviewed our other video metrics on the dashboard and have found that this has no impact on video numbers we have shared in the past, such as time spent watching video or the number of video views."
In a separate post in Facebook advertiser help center a month back, the company has further clarified the definition of its metrics. According to this post, both Average Duration of Video Viewed and the Average per cent of Video Viewed will be replaced with Video Average Watch Time (the total watch time for a video, divided by the total number of video plays, including autoplay) and Video Percentage Watched (percentage of video somebody watches per session, averaged across all sessions of the video) respectively.
So how much does it actually impact marketers and their ad spends? As reported by TechCrunch, Azania Andrews, Senior Director (Digital Connections) at AB Inbev, in a tweet about the controversy, called it "silly".