Facebook VP EMEA on advertising measurement: “We don’t always get it right”

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Facebook's EMEA vice president Nicola Mendelsohn has said that the platform wants to be open and honest with businesses when it comes to reporting the effectiveness of advertising.

Facebook reported last year that some of the metrics it provides to advertisers and publishers were inaccurate, and in February let the Media Ratings Council (MRC) audit the accuracy of some of the data it gives brands.

Then last week it found a bug that wrongly attributed mobile video carousel ad clicks to clicks to advertisers' websites, and refunded some clients as a result.

"We want to be the most open, honest and transparent platform in the world when it comes to measurement and sometimes we don't always get it right. There might be a bug that can come along the way as we had last week," Mendelsohn told CNBC by phone.

Nicola Mendelsohn is vice president of Facebook EMEA

"And I think, we are not 100 percent perfect – other platforms aren't either – but we want to be held accountable and we will put our hands up, we will tell you what's gone wrong and then we'll take the appropriate action, and it might cost us in the short term," she said.

Facebook now has 24 measurement partners and in March, it opened up its advanced measurement tool to more advertisers, not just the largest ones.

Mendelsohn added that Facebook is "obsessed" with how technology can drive business growth, and urged brands to have effective digital and mobile strategies, criticizing advertisers for simply putting adverts made for TV on to the platform, without considering viewers' very short attention spans, especially on mobile.

Speaking to CNBC by phone following a speech she made to an internet conference in Amsterdam this week, she said:

"(There is) general agreement from everybody now that mobile has radically changed the way in which people are discovering, sharing and experiencing content and especially video content. Businesses are struggling to keep up and that's actually a major disconnect that is causing greater disruption across industry," she said.

On average, people spend 1.7 seconds looking at content on their Facebook news feed on their smartphones, but this figure multiplies by five for videos, Mendelsohn added.

She said there are variety of ways that people watch video on mobile, including on the go, "when you've got short moments where you are probably multi-tasking," the "lean-forward moment," when someone ends up in a "rabbit hole" of content, and "lean back," where someone might watch an episode of a show.

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