Media Companies’ Survival Depends on More Accurate ROAS Measurement
Guideline Spend is a census of all media dollars transacted through the biggest 12 agencies in the US market.
Do you hear that giant sucking sound? That’s the advertising economy draining billions into the bank accounts of Google, Meta, and Amazon
Why do advertisers keep shifting more and more of their budgets to these digital giants, year after year, at the expense of other media companies? Sure, they have eyeballs and engagement, but that’s only part of the story.
If this were a (very lousy) game show—Advertising Family Feud—the top answer would be obvious: “Measurability!” Ding, ding, ding!
For most media companies outside the Big Three, proving their ROI has been historically undervalued due to flawed ad performance measurement is now an existential priority. Engagement metrics, attention scores, brand impact studies, attribution models, and quasi-experimental lift reports won’t cut it. Neither will claims about “quality audiences” or other vague promises.
Even mediocre marketers are skeptical of these metrics. The smartest ones outright dismiss them as irrelevant to what matters most: incremental sales impact.
So, how can media companies bridge the gap and prove their value?
The Case for Geographic Experimentation
The easiest and most effective way to deliver what advertisers need—transparent and credible proof of ROI—is by implementing sound geographic experimentation. Better yet, develop an in-house center of excellence around this approach.
Big Digital has spent years perfecting its tools for “proving” (and often feigning) ad performance. These include:
Marketing Mix Modeling (MMM) tools like Google’s Meridian and Meta’s Robyn.
Auction-based randomized experiments, also known as “ghost ads,” which Apple’s privacy measures have impaired in recent years.
Black-box AI optimization engines like Google’s Performance Max and Meta’s Advantage+, which are difficult to validate independently.
These tools make it easy for advertisers to spend more, while other media companies struggle to offer competitive proof of performance. Resistance to Big Digital often feels futile—but it doesn’t have to be.
TV, Radio, and Outdoor: Still Undervalued
It’s likely that TV ROI is undervalued. The same goes for traditional channels like radio and outdoor, which still capture attention just as effectively as ever. But without credible evidence of their true impact, they’ve largely fallen off the marketing mix radar.
And what about other digital properties? Are they outperforming Meta and Google? With today’s ROAS measurement practices, it’s anyone’s guess.
DMA Testing: A Path Forward
DMA-based experiments could be the best hope for media companies looking to prove their value. As discussed in my recent AdExchanger article, ZIP-code-based targeting could take things a step further, but it would require heavier lifting by media companies, and I’m not holding my breath.
Large-scale, randomized DMA experiments are emerging as a powerful, scalable method for ROAS measurement. By randomizing all 210 DMAs into test and control groups, advertisers can conduct transparent, replicable tests that provide irrefutable ROI evidence. Compared with user-level experiments, large-scale geographic experiments are far easier to implement, much less costly, and more accurate, due to noise and matching-biases in user-level frameworks.
This was a key topic in our recent webinar with MASS Analytics, an MMM specialist, describing how MPE (Models Plus Experiments) is a growing practice to calibrate the accuracy of mix models with regular ROAS experiments.
The Bottom Line
Media companies that adopt these rigorous testing methodologies, or even make them simple for advertisers to implement independently, have their best shot at countering claims of superior performance Google, Meta, and Amazon. If your channel truly adds value, transparent experiments will prove it—turning your “measurability gap” into a competitive advantage.
In a world dominated by Big Digital, investing in accurate ROAS measurement isn’t just a strategy—it’s a survival necessity.
Post Script
Thanks to Guideline for permission to share this data.
As Josh Chasin and Susan Hogan pointed out in the comments of this post on LinkedIn, that 29% share of spending shown in the chart is an even smaller share than the Big Three command of the total ad market, as Guideline's data includes only the spending of the largest ad agencies. Even more of the total goes to the biggest players thanks to the "long tail" of the market that does not go through the biggest agencies (i.e., through smaller agencies, large advertisers in-housing, and smaller advertisers buying direct).
Thankfully, large agencies still diversify their budget across more publishers compared to smaller advertisers, but even there the trend is not promising for the majority of media companies.