Display advertising has become extraordinarily sophisticated at measuring whether an ad was delivered, viewable, clicked or even noticed. But one fundamental question is still rarely measured: was it relevant to the person seeing it? Relevance sits at the intersection of audience, context and creative- whether the right message reaches the right person in an environment and at a moment where it makes sense. Yet while the industry has developed established metrics around reach, viewability, attention and performance, Relevance has remained much harder to define and quantify. RAAS Lab, alongside agency partners, explores why Relevance could be the missing metric in display advertising. What actually makes an impression relevant? Can it be measured consistently? And if advertisers can understand Relevance alongside traditional media metrics, could it help planners make better decisions, improve campaign effectiveness and ultimately connect media investment more closely to business outcomes?