What is incrementality?
Incrementality in marketing refers to the additional impact your campaign has—measurable growth that wouldn’t have occurred without it. In essence, it quantifies what actually changed thanks to your campaign, rather than simply tracking who clicked or viewed.
Traditional attribution models (like last-click or multi-touch) often over-assign credit by assuming any action linked to an ad was caused by it—without proving causation. Incrementality, on the other hand, focuses on real influence:
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Causality over correlation
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Budget optimization by investing in activity that delivers actual lift
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Clear ROI insight—understanding what your campaign earned, rather than just claimed
How Incrementality Testing Works
A/B Test Framework
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Create Groups: Divide your audience into a test group (where the marketing runs) and a control group (where it doesn’t).
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Run the Campaign: Only expose the test group to your ads or messaging.
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Measure Results: Compare outcomes across both groups to calculate true lift.
Incremental Lift=Test Group Outcome−Control Group Outcome
Alternative Methodologies
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Geo-lift Studies: Use geographical regions as test/control segments for broader campaigns.
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Advanced Statistical Techniques: Causal inference models can estimate lift without pausing campaigns.
Incrementality vs. Attribution
| Metric Type | What It Measures | Key Difference |
|---|---|---|
| Attribution | Assigns conversion credit to channels | Shows correlation, not causality |
| Incrementality | Measures causal impact and added value | Answers “Did this campaign create results?” |
Applications of Incrementality
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Channel Analysis: Identify channels that genuinely drive new conversions.
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Campaign Evaluation: Measure how much lift each creative or strategy provides.
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Budget Optimization: Direct spend to activities that deliver positive ROI and pause those that don’t.
Challenges & Best Practices
| Challenge | Best Practice |
|---|---|
| Small sample sizes | Scale adequately to ensure statistical significance |
| Group contamination | Keep test/control groups isolated (e.g., use geographic segmentation) |
| External factors skewing results | Include seasonality or context in test design |
| Complexity in attribution models | Supplement findings with MMM for full channel visibility |
Real-World Example
Imagine Campaign A led to 1,000 conversions; however, tracking the control group reveals 800 conversions would have occurred without it. Your true incremental impact?
200 conversions directly attributable to the campaign.
Incrementality marks a shift in marketing measurement—from claiming credit, to proving contribution. It is critical for agencies and marketers aiming to spend smarter, prove ROI, and build growth based on causality—not assumptions. When paired with MMM and attribution strategies, it gives a full, accurate understanding of what drives business forward.