By James Milne, SVP Business Development at Epsilon
If you’re a fan of the cult classic Ghostbusters, you’ll know the most important rule: don’t cross the streams.
In the world of CTV, most brands follow the same instinct, keeping their video channels separate to avoid overexposure, audience overlap, duplicated spend and wasted budget. It’s a sensible-sounding approach, but it’s also where things start to go wrong.
There’s something strange on your CTV
In the UK alone, 20 million households subscribe to streaming services, on average 2.9 each, and watch nearly three hours of streaming content a day (BASE report, 2024). Moments like this summer’s World Cup, expected to be followed by 34 million UK adults, should represent a clear opportunity for brands to reach engaged audiences at scale.
The common response to all this inventory has been to find the right video channel for your audience and optimise within it. Brands buy CTV as its own line item, measure it against its own KPIs, and keep it separate from whatever else they’re running across display, online video or retail media. When CTV is measured in isolation, though, the learning stays siloed: you can see how many people completed a view, but you can’t see what happened afterwards or whether that exposure contributed to anything meaningful further down the line. The budget comes under pressure, and brands risk pulling back from a channel before it’s had a fair chance to prove its value.
One stream is never enough
Audiences don’t stay in one place, and the World Cup illustrates the point well. Epsilon’s recent research found that 71% of fans surveyed won’t just be watching the game, they’ll be messaging friends, checking stats, scrolling social feeds and spending money. Between fixtures they’re spread further still, taking in commentary and analysis across BBC and ITV (41%), Sky and TNT Sports (32%), YouTube (27%) and official apps and websites (22%). This kind of cross-platform behaviour reflects how consumers generally move between screens, formats and moments throughout the day, and when brands activate in just one of those environments they’re only seeing a fragment of how their audience actually behaves.
The measurement picture is equally uneven. Broadcast Video on Demand platforms like ITVX can connect a logged-in user to a household, offering a relatively reliable signal, while subscription services like Apple TV or Disney+ match an authenticated person to an account. Across FAST channels and broader CTV inventory, though, consistent identification is rare, signals are unstable and users span multiple devices and apps. Without a unified view, frequency management breaks down, attribution becomes unreliable and brands either overexpose one household while missing others entirely or spend more than they need to without knowing it.
Being honest about what CTV can and can’t do
There is a temptation to position CTV as a full-funnel performance channel held to the same standards as display or paid search, but that overstates what the technology can do today. CTV confirms an ad was served to a device in a home, not who in that household actually watched it. Treating a single impression as equivalent to a verified one-to-one interaction is a claim the data doesn’t support. The more defensible position is that CTV works well for reach and early-stage awareness, and that its measurement sharpens considerably when it forms part of a connected, multi-channel approach.
Cross the streams
Rather than measuring CTV in isolation, brands should stop isolating it in the first place. When CTV, online video and display are activated together, a much more complete picture emerges of who is being reached and how frequently. CTV provides the reach and awareness, while channels that operate at the person level, like mobile and display, provide the individual signals that connect exposure to behaviour. A persistent identity layer, grounded in real data, is what ties the two together, and it’s that connected foundation that makes frequency, attribution and incrementality genuinely reliable.
What changes most when brands get this right is the ability to capture the upper-funnel journey properly. Rather than treating awareness as a line item that’s hard to justify, brands can see the sequence of interactions that follows a CTV exposure: shifts in brand recall, increases in search activity, growth in product page engagement, rising visit frequency. These are high-quality signals that reveal the demand being built, and they’re only visible when activation runs across channels rather than within them. That demand converts, whether at key commercial moments or during a seasonal peak brands have been building towards for months.
The streams were never meant to stay separate. The value was always in crossing them.
