Marketing has never been more complex – or more distracting. CMOs are expected to master a growing web of platforms, data sets, technologies and tactics, all while proving value in boardrooms that are increasingly numbers-first. Somewhere between CDPs and CACs, CRMs and MMMs, we tend to level out.

So, it’s time to bring it all back to basics with a little something called essentialism.

Popularised by Greg McKeown in his 2014 book Essentialism: The Disciplined Pursuit of Less, the idea is simple but powerful: focus only on what truly matters and cut everything else. It’s about doing less, but better. And in the world of marketing, there is no clearer application than putting the spotlight on a single, unifying metric: MROI.

MROI – or marketing return on investment – has been around for years. But despite its universal relevance, it remains underused, undervalued and often misunderstood. We’ve built an industry obsessed with micro metrics like CTR, CPC and CPM without always asking the bigger question: is this actually working?

MROI offers a high-level, boardroom-ready view of marketing effectiveness, showing how every dollar spent contributes to business outcomes. When underpinned by a reliable marketing mix model (MMM), it becomes the CMO’s most powerful tool – not just for measurement, but for focus.

Plus, it really saves time. A clear MROI trend line gives CMOs a quick pulse check: are we improving the brand baseline? Are our performance channels delivering? No deep dive required. It simplifies the conversation. Forget reporting on 20 different metrics across five platforms. MROI gives teams a north star; a single, financial measure that boards, CFOs, and marketers can align on.

It also drives accountability. Rather than asking “How did that campaign perform?”, CMOs can now ask “Did we grow MROI this month?”. If the answer is no, the team knows where to dig. If yes, we double down. And it reinforces progress. A robust MMM will show short-term direct response returns alongside long-term brand-building impact. MROI turns abstract marketing efforts into visible, measurable outcomes.

The below chart is a simplified MMM outcome and is, potentially, all that the CMO needs to view and discuss about media performance. The blue area represents sales over time attributing to non-media activity, the red area represents the sales arising from media activity.  The CMO simply needs to hold the media team to account on the red area. There is a lot of detail that drives both lines, but the focus on these two areas brings clarity and simplicity to the team. The MROI is clarified and unavoidable in this one simple, essential graph.

We’re in an era of marketing overload. AI tools are going gangbusters, and they all promise more automation. Platforms demand more content. Budgets demand more justification. But with this explosion of complexity, the most valuable thing a CMO can do is simplify.

Essentialism teaches us that focus is a choice. And in media, where we so often confuse noise with impact, choosing to focus on MROI is a way to cut through the confusion.

MROI needs to become a universal metric for marketing effectiveness – across all categories, channels and contexts. It offers the clarity, simplicity and accountability that marketing teams need and leadership demands.

As the complexity of marketing keeps growing, our metrics shouldn’t follow suit. Let’s not just measure more. Let’s measure what matters.

This story is part of Mi3’s full collection of industry trends, debate and developments from Future of TV Advertising ’25 which will roll out over the coming week in our editorial series here.