Measuring the Incrementality of Facebook
Understanding Your Options

In the world of digital advertising, the term "incrementality" has become increasingly important. Advertisers want to know not just whether their campaigns are driving conversions, but how many of those conversions would have occurred without the ads. In essence, incrementality measures the true causal impact of your advertising efforts, cutting through the noise to identify real, attributable results.

With Facebook Ads (or Meta Ads Manager campaigns), measuring incrementality is both crucial and challenging. Facebook offers in-platform tools like Conversion Lift Studies and GeoLift Experiments, while the INCRMNTAL platform offers a different perspective. Each method is valid and serves a specific use case, but understanding the nuances of these approaches is key to choosing the right one for you. 
Let’s explore each option in detail and provide a side-by-side comparison to guide your decision-making.

First and foremost: Why incrementality matters?

The digital advertising ecosystem has evolved dramatically in recent years, driven by privacy changes, platform restrictions, and growing skepticism about attribution. Relying on last-click attribution or vanity metrics such as CPC, CTR, or Assisted installs often leads to inflated or misleading results. Here’s why incrementality is a game-changer:

1. Accurate ROI Measurement: Incrementality reveals the true return on investment (ROI) of your campaigns by isolating the impact of your ads.
2. Avoiding Overlap: Many conversions might occur due to other factors—organic traffic, word of mouth, or other channels. Incrementality helps identify how much is truly driven by your ads.
3. Optimizing Spend: Knowing which campaigns are driving incremental results enables you to allocate budgets more effectively and cut waste.

With this context, let’s dive into the three main ways to measure the incrementality of Facebook Ads.

Option 1: Conversion lift study (true randomized control trial)

A Conversion Lift Study is Facebook’s in-platform solution for incrementality measurement. As a true randomized control trial (RCT), this approach provides scientifically rigorous results, but it does have its limitations. 
Head over to Meta Ads Manager Experiments area and choose “Conversion Lift”. Follow the steps to setup a conversion lift study. 

How it works:

• Facebook randomly splits your target audience into two groups: 
  • Test Group: This group sees your ads.
  • Control Group: This group does not see your ads.
  • After running the campaign, Facebook compares the behavior of the two groups to calculate the incremental lift in conversions caused by the ads.
     

Advantages of conversion lift studies

1. Scientific Accuracy: Randomization eliminates biases, ensuring that any difference between the groups is due to the ads.
2. Direct Integration: The study is seamlessly built into Facebook Ads Manager, making it easy to set up and analyze.
3. No Additional Cost: Facebook does not charge extra for conducting the study (beyond the cost of running the campaign itself).
    

Challenges of conversion lift studies

1. Platform-Specific Insights: This method only measures the impact within Facebook’s ecosystem. If your customers interact with multiple channels (which is highly likely), the lift study won’t capture the full picture. 
   i.e. if you’re running campaigns with Google (+90% global reach), or TikTok (+80% global reach), or any other channels – you will have no way to control if or where your test and control users may see your ads. 
2. Large Sample Size Requirements: Statistically significant results require a sufficiently large audience, which may not be feasible for smaller advertisers.
3. Opportunity cost and time: To gain statistical significant, a conversion lift study need to run for several weeks, delaying insights that could drive faster decision-making.
    

Option 2: GeoLift experiment

GeoLift is Facebook’s regional incrementality testing tool. Instead of randomizing individuals, this method compares geographic regions where ads are active versus regions where they are paused.

Running a GeoLift test with Meta Ads Manager is slightly more complex than a conversion lift study, as it requires you to exclude certain regions from campaigns to control the areas where audiences will be exposed to your ads vs. ones you’ll holdout ads from. 

How it works

• Select two comparable sets of regions: 
  • Test Regions: Ads are shown.
  • Control Regions: Ads are paused.
• Measure the difference in conversions between the two groups of regions.

GeoLift experiments are especially valuable for advertisers with physical locations or regional campaigns.

Advantages of GeoLift

1. Real-World Testing: By testing in natural conditions, GeoLift reflects actual consumer behavior.
2. Privacy-Compliant: This method does not rely on user-level data, making it ideal for the post-IDFA/post-cookie era.

Challenges of GeoLift

1. Complexity: Designing a successful GeoLift experiment requires careful planning. Regions must be similar in characteristics (e.g., demographics, purchasing behavior) to ensure valid comparisons.
   You also need to try and plan for the unplanned – external variables that may influence and “taint” the result of your test – such as localized events, activities, holidays, and whatever variable may affect your marketing results. 
2. Limited Granularity: While GeoLift captures broad trends, it may not provide granular insights into specific audience segments or tactics.
   
    

Option 3: INCRMNTAL

INCRMNTAL offers an innovative approach to incrementality measurement. Unlike Conversion Lift or GeoLift, INCRMNTAL does not require control groups or manual test design. Instead, it leverages machine learning and statistical models to estimate the causal impact of your campaigns.

All you need is to integrate your marketing data and ad spend using the INCRMNTAL UI and after the models are run once – the platform will show you the incremental value for all of your Facebook campaigns down to daily granularity. 

How it works

• The platform analyzes historical data, campaign performance, and external factors (e.g., seasonality, promotions) to determine the incremental lift of your ads.
• Insights are delivered continuously, without the need to pause campaigns or split audiences.
   

Advantages of INCRMNTAL

1. Holistic Measurement: INCRMNTAL tracks the combined effect of all your advertising efforts across channels, not just Facebook.
2. Always-On Insights: Real-time analysis enables advertisers to optimize campaigns on the fly.
3. Scalable: Works for campaigns of all sizes and budgets, making it accessible to both small and large advertisers.
4. No Interruption: Unlike traditional RCTs, there’s no need to pause ads or exclude audiences.
    

Challenges of the INCRMNTAL platforms

1. Cost: While the Facebook Ads Manager incrementality tools are free – INCRMNTAL does have a monthly license fees and may only fit clients already operating at a certain scale.
2. Learning Curve: Understanding advanced methodologies and trusting the results may take time for teams unfamiliar with incrementality concepts.
3. Data Dependency: The accuracy of results hinges on the quality and completeness of your input data.

How to choose the right method for you ?

Each of these methodologies has its place, depending on your goals, budget, and constraints.

• If you are only running Facebook Ads: Conversion Lift Studies are the simplest and most reliable option, provided you have the budget and audience size.
• If you only want to measure incrementality as a one off: GeoLift experiments are ideal for understanding how your ads drive results.
• If you need a holistic, always-on solution: INCRMNTAL is perfect for advertisers who want a complete view of their marketing impact without disrupting campaigns.

Incrementality measurement options 

Here’s a side-by-side comparison of the three methodologies:
 

Final thoughts

Measuring the incrementality of Facebook Ads is no longer optional—it’s essential for advertisers looking to drive meaningful results in today’s complex landscape. Whether you choose a Conversion Lift Study, a GeoLift Experiment, or a platform like INCRMNTAL, the key is to align your methodology with your goals.

Incrementality isn’t just about proving your campaigns work—it’s about making them work smarter. Choose the right tools, and you’ll unlock the insights needed to optimize your ad spend, improve ROI, and make your marketing strategy truly data-driven.

FAQs

1. How does Facebook’s “Incremental Attribution” feature fit in?

The newer Meta tools (e.g. “Incremental Attribution” windows and optimization-focused lift campaigns) are designed to help advertisers optimize for net-new conversions rather than simply attributing existing ones. Early clients report improved Cost Per Acquisition (CPA) performance by focusing on incremental sales .

2. What is the ROAS formula for Facebook?

The basic ROAS (Return on Ad Spend) formula is:
ROAS = Revenue from Facebook Ads / Cost of Facebook Ads
For example, if you earned $500 from a Facebook campaign that cost $100, your ROAS is 5.0 (or 500%).

3. Why is incrementality more reliable than click-based metrics?

Click-based metrics (like last‑click, CPC, CTR) can inflate results due to overlap from other channels or organic traffic. Incrementality isolates your ads’ real influence, avoiding misleading attribution.