CHICAGO – Of the many pieces of data being brought to the video ad chain by software developers, amongst the most important should answer the question: “Is this video really being watched by a viewer?”

TubeMogul CEO Brett Wilson’s company has open-sourced code to let advertisers see what percentage of a video window is really in-view. But he thinks such data will soon make waves when it becomes more commonly available.

“I think, by the end of the year, you’ll start seeing some kind of standard around video viewability,” Wilson told Furious Minds CEO Ashley Schwartz in this taped interview at Beet.TV’s programmatic video advertising summit. “What percentage of video is viewable? We think it’s going to be pretty shocking once people start running these reports – maybe 50% of video right now is viewable.”

Such a number could spook many advertisers. But Wilson says the data will help distinguish quality traffic from poor.

“What happens when you roll out viewabiity is you expose the bad behaviour and the good behaviour. CPMs will go up for the best sites – big players that feel TV-like.” Losers from viewability data will include sites that try fooling the numbers by auto-playing videos in banners and playing third-party video, Wilson added.

Disclaimer: TubeMogul sponsored the summit on programmatic buying at VivaKi.