You’ve Run an Incrementality Test—Now What?

by Ben Dutter •

Incrementality testing is becoming a staple in marketing measurement, with more brands leveraging it to assess their media effectiveness. We’ve conducted over 1,000 incrementality tests, and we work with many clients who also rely on other partners for this type of measurement.

But here’s the issue: many brands use incrementality testing incorrectly.

The purpose of measurement is to gain information. The purpose of information is to make decisions. If you’re running tests just to validate assumptions, look busy, or appear informed, you’re missing the entire point.

The Right Approach to Incrementality Testing

Before running a test, it’s important to ask yourself the following questions:

  • What decision am I trying to make? Clearly define the problem or opportunity you want to address.
  • What information do I need to make that decision? Identify key metrics and data points that will inform your next steps.
  • What actions can I take based on the results? Determine how different outcomes will affect your media strategy and budget allocation.

The first and most common mistake brands make is testing without a clear purpose. They hear “you should be doing incrementality testing,” and they dive in—without defining what they actually want to solve. A well-structured test should always lead to a concrete action plan.

You’ve Done the Test. Now What?

Let’s say you run an incrementality test, and the results come back with an incremental return on ad spend (iROAS) of 3x. That means for every dollar spent on that channel, you generate $3 in incremental revenue.

Now let’s assume your brand needs a 2x iROAS to be profitable. Since 3 > 2, this channel is profitable. Great!

Currently, the channel represents 10% of your media budget, with a monthly spend of $50,000. But here’s the problem: most brands don’t adjust their budgets based on these insights. They gain valuable data—but then do nothing with it.

How to Take Action on Incrementality Test Results

If the test results indicate a strong iROAS, here’s what you should do:

  1. Increase the budget from $50K to $60K per month. A profitable channel should be scaled strategically.
  2. Keep everything else stable to ensure consistency and control. Drastic changes can introduce new variables that make it harder to measure impact.
  3. Monitor total revenue against historical baselines. The key is to assess whether the increased investment is driving proportional gains.

If total revenue increases and remains stable, you’ve successfully scaled. If results are inconsistent, run another test after a stabilization period (about a month). If you need quicker insights, set up a new test in a different market or audience segment.

What If the Results Are Negative?

Not all incrementality tests yield positive results, and that’s okay. If a channel is showing a low or negative iROAS, you should consider:

  • Reducing or reallocating budget to higher-performing channels.
  • Testing different ad creatives or messaging to improve engagement and conversions.
  • Optimizing audience targeting to ensure your ads are reaching the right users.
  • Exploring additional factors such as seasonality, pricing, and competitive dynamics that might be impacting performance.

The Key Takeaways

To ensure you’re using incrementality testing effectively:

  1. Don’t test just to test—always tie your measurement to an actionable business decision.
  2. Define the key decisions you need to make before designing the test.
  3. Structure your test to provide relevant insights that inform those decisions.
  4. Act on the results—adjust budget allocations, optimize campaigns, and iterate as needed.
  5. Analyze both positive and negative results to continuously refine your marketing strategy.

Need Help Interpreting Your Incrementality Test?

If you’ve run an incrementality test but aren’t sure what to do next, fusepoint can help. We provide data-driven insights and strategic recommendations to turn measurement into action. 

Book a consultation today and start making data work for your business.