Only 32% of marketers measure media holistically across digital and traditional channels, according to Nielsen. The other 68% are making budget decisions with partial scorecards. On October 20, IAB dropped a draft that tries to fix the workflow behind those decisions, not just the math.
What IAB Actually Released
The Cross-Channel Measurement Decision Guide, built under IAB's Project Eidos, is open for public comment through November 4, 2026. It's structured around a simple premise: start with the business decision, then work backward to the evidence that can inform it. Not the other way around.
That sounds obvious. In practice, most teams do the opposite. They start with whatever dashboard is open, then retrofit a narrative to justify a budget move. Three connected pieces make up the draft:
- Decision Guide: A sequence from business outcome to decision, measurement question, evidence, interpretation, and action.
- Decision Navigator: Applies that sequence to common scenarios (allocating budget across channels, assessing whether a channel generates incremental value) and helps users figure out which method fits which question.
- Measurement Reference Library: Metric definitions and supporting context so teams aren't arguing about what "ROAS" means in a given analysis.
David Cohen, CEO of IAB, put it plainly: "This guide doesn't ask marketers to pick a winner among those methods. It gives them a disciplined way to work through the question at hand and make a decision they can stand behind."
Why "Decision-First" Matters for Ops
If you run marketing ops or RevOps in B2B SaaS, you've lived the version of this problem where MMM says paid social drives 40% of pipeline, attribution says it's 12%, and your CFO asks which number is real. The honest answer: they're answering different questions at different levels of aggregation. Forcing them to reconcile into one "source of truth" is where teams get stuck.
The practical consensus is straightforward: MMM fits strategic budget allocation across channels; multi-touch attribution works for tactical, in-flight optimization where user-level tracking is reliable; incrementality experiments validate whether marketing actually caused additional outcomes. The problem isn't that they disagree. Teams treat all three as interchangeable answers to the same question.
Matt Shapo, Senior Director of Measurement at IAB, framed the goal: "The real test is whether it holds up in an actual planning conversation, like when a channel reports a strong attributed ROAS that an incrementality test doesn't back up." That scenario is not hypothetical. It's Tuesday.
The Part the Guide Can't Fix
A decision framework is only as good as the data flowing into it. Cross-channel deduplication remains genuinely hard because platforms report reach within their own environments. Add up self-reported reach numbers from three walled gardens and you'll almost certainly double-count the same person. Without a shared identity or deduplication method, you're working with estimates, not census-level truth.
This matters especially if you're expanding into CTV, audio, or retail media. A Nielsen cross-screen study (five brands during India's IPL) found less than 5% audience overlap across linear TV, connected TV, and mobile, with 20%-40% incremental reach from cross-screen plans. Those numbers are context-specific (market, event, platform mix). Treating them as universal benchmarks for your B2B SaaS media plan would be a mistake, but the directional point stands: overlap is lower than most teams assume.
The guide won't solve walled-garden data access constraints or inconsistent exposure definitions. What it can do is give your team a shared vocabulary for acknowledging where the evidence is strong, where it's directional, and where you're flying blind.
What to Do Before November 4
IAB is specifically asking whether the guide reflects real-world measurement decisions, whether the method-fit guidance holds up when results conflict, and whether the scenarios are realistic for day-to-day planning. If you've spent any time reconciling MMM output with platform attribution in a planning cycle, you have opinions worth submitting.
It just makes those disagreements productive instead of paralyzing.
Cohen's framing of the maturity gap is worth sitting with: "60-75% say advanced measurement falls short across key dimensions such as rigor, timeliness, trust, and efficiency." A guide won't close that gap on its own. But a shared framework for which evidence answers which question, agreed on by marketers, agencies, and measurement partners before the next planning cycle starts, is the kind of infrastructure that compounds. The 15-day comment window closes November 4. The measurement arguments, of course, will continue well past that.
