The appeal of being in this digital age of marketing is that everything is supposed to be measurable. However, if a recent study is accurate, we may not be as locked-in on some audiences as we think.

According to a 2017 study by Omnicom Media Group and Hearts & Sciences, 47 percent of adults between ages 22 and 45 watch no content on traditional TV platforms. It’s not that they are not watching shows or even seeing ads, they’re just using different platforms to do it.

This hybrid audience consisting of Generation Xers and Millennials are streaming apps (Netflix, Hulu, Amazon and YouTube) through devices such as Roku, Apple TV, gaming consoles and smartphones to consume their shows. Here’s the problem for advertisers: two-thirds of the TV and video watched by this group is not accounted for by traditional measurements.

So far, Nielsen ratings – the standard for reporting the practices of television viewers – have not been able to measure these non-traditional platforms, underscoring the flaws in our current tracking system and indicating a need for change.

The Omnicom study deems this hybrid audience unreachable and that’s a problem when you consider the spending habits of these two generations.

“It’s pretty scary. We (marketers) are not reaching young audiences effectively, just over-indexing on older viewers on TV,” says Hearts & Sciences CEO Scott Hagedorn. “We are headed toward a creative wake-up call.”

Chris Phillips, Chief Product Officer of Pandora, says publishers must “want to get to a transparent, open source SDK (software developer kit) that will work across all the different measurement providers, and across all the publishers, platforms, and devices to give consistency to the ad buyer.”

Change is happening. For instance, if you stream the Hulu app through your PS4 or Xbox One, you may notice you are being served more commercials for video games than if you were streaming it on your smartphone.

However, until there is a cohesive system to track audiences through all platforms, brands need to focus on what they know about their audience and use that information to craft their messaging. After all, even in times of great change, basic marketing principles still hold true.