Proving marketing’s impact has never been more important or more challenging. Marketing leaders are under constant pressure to prove ROI, while finance teams and executives want clear answers to a simple question: Is our marketing actually driving incremental revenue?
To answer that question, many organizations are building more advanced measurement solutions like Media Mix Modeling (MMM). MMMs are powerful tools for long-term decision-making, but a business-ready model requires time, data maturity, and cross-functional alignment. While that work is underway, leaders still need clarity, and marketers need to make confident decisions about where to invest.
Always-on media holdout testing offers a practical and credible way to meet those needs. It delivers a clear view of incrementality today, builds confidence with leadership, and lays the foundation for deeper measurement over time.
What Is Always-On Holdout Testing?
Always-on holdout testing is a geographic-based testing approach that works by creating a true baseline. A small, carefully selected set of geographic markets does not receive any paid media across any channel, showing what business performance looks like without marketing. The rest of the country continues running paid media as usual.
By comparing performance between these test and control geographies, marketers can isolate the incremental impact of marketing on sales. At Ovative, we isolate small portions of the US market, roughly 5%, at any given time. These markets rotate over time, allowing brands to measure continuously without permanently limiting growth.
When to Use Always-On Holdout Testing
Always-on holdout testing is not the answer to every measurement question, but there are clear moments when it delivers value. Below are three common scenarios when geo-based always-on holdout testing helps teams gain clarity, build confidence, and make smarter decisions:
1. When You Don’t Have an MMM
Platform reporting and last-click attribution only tell part of the story and often miss the bigger picture. Without a model, it is difficult to understand how channels work together or how marketing drives store sales, ecommerce, and omnichannel behavior.
Always-on, cross-channel holdout testing fills that gap by capturing media’s full business impact. It provides strong directional guidance and is the closest thing to a full-funnel view without a model.
2. When Leaders Need Clear Answers
If senior leaders are unsure whether marketing is truly driving growth, or if prior measurement has been inconsistent, always-on testing can reset the conversation. A well-designed geo-based cross-channel holdout delivers a straightforward and defensible result, showing the incremental revenue marketing generated compared to doing nothing.
That clarity builds trust quickly, aligns marketing, finance, and executives around a shared understanding, and provides a strong foundation for smarter investment decisions.
3. When You Want to Increase Media Spend
Scaling spend, leaning into upper-funnel channels, and reaching new audiences often requires hard proof before unlocking additional dollars. Always-on holdout testing shows whether the current media program is:
- Under-delivering and in need of adjustment, or
- Creating incremental value and ready to scale
With transparent, causal results, marketers can confidently advocate for growth using data that finance and executives trust.
How to Set Up Always-On Holdout Testing for Success
Like any measurement approach, always-on holdout testing only works when it’s designed and executed thoughtfully. Because geography is the only variable being manipulated, careful planning is essential. The following best practices help ensure your results are credible, actionable, and useful today while supporting more advanced measurement in the future:
1. Set Clear Testing Expectations
Models and tests serve different purposes. Models guide long-term decisions around mix, allocation, and saturation. Tests measure short- to medium-term causal impact at a specific point in time.
For brands without an MMM, always-on tests validate strategy and planning, but they’re not designed to answer every long-term optimization question. Aligning on expectations upfront prevents misinterpretation and builds trust in the results.
2. Start with a Clear Hypothesis
Successful tests begin with intent. Avoid approaching testing with the mindset of “let’s see what happens.” Instead, define what success looks like ahead of time. A strong hypothesis is specific, measurable, and feasible. Understanding what a successful incrementality rate for your business looks like makes results easier to interpret and turn into action.
3. Plan Proactively
The strongest tests are designed in advance, not added as an afterthought. Proactive planning leads to better data and stronger confidence in the results.
Build testing into annual planning cycles. Establish a regular cadence for rotating test and control geographies. Give channel teams and partners enough time to plan exclusions, QA setups, and execute cleanly.
4. Choose the Right Markets
Geo-based testing only works when test markets represent the broader business. If holdout markets differ meaningfully in demand, demographics, or distribution, results will be skewed. Careful market selection is critical to producing insights leaders can trust. At Ovative, we use our EMRge™ marketing intelligence platform to match our clients’ markets based on proximity, performance, and predictability.
5. Combine Total Media and Channel-Specific Tests
Always-on total media geo holdouts measure how the entire marketing program performs together, creating a benchmark for overall effectiveness. Channel-specific holdouts then measure the incremental value of individual tactics, providing important context and supporting future media mix modeling.
For example:
- Total Media iROAS: 3.25
- Search iROAS: 4.30
In this case, search is outperforming the program average, making it a strong candidate for additional investment. Without the total media benchmark, it isn’t easy to judge whether a channel is truly strong or simply benefiting from the rest of the mix.
Unlock True Growth with Always-On Holdout Testing
For brands without an MMM, always-on geo-based holdout testing is one of the most credible and actionable measurement tools available. It shows the true incremental impact of marketing on the business, builds trust across teams, and supports smarter investment decisions. Always-on testing does not replace modeling; it prepares organizations for it. And for many brands, that preparation is what makes confident growth possible.
For brands with an MMM in place, always-on cross-channel holdout testing can be a powerful complement. When grounded in a clear understanding of sales risk and opportunity cost, these tests help reinforce confidence in marketing impact and evaluate incremental upside. Rotating channel-specific holdout tests when an MMM is strong further enhances the model. These tests help validate model outputs, refresh priors, and translate insights into clear, confident action. By grounding model recommendations in real-world causal evidence, testing strengthens decision-making and increases leadership confidence in where and how to invest.
Need help getting started? Our measurement team is well-versed in always-on holdout testing. Partner with Ovative to design a program that clearly demonstrates the true impact of your marketing.
