Incrementality
The additional impact of an ad
In short
Incrementality is the share of conversions that wouldn't have happened without an ad or campaign. It's measured with tests against a control group.
Also known as: incremental conversions, incrementality test
Incrementality describes how many additional conversions an ad or campaign brings, meaning conversions that wouldn't have happened without it. It's the counterpart to attribution: attribution says who gets credit for a conversion, incrementality says whether the ad caused it.
Example
A retargeting campaign is credited with 100 leads in the ad account. A test with a control group shows that 70 of those people would have inquired without the ads:
Incremental leads = 100 - 70 = 30
Incrementality = 30 ÷ 100 = 30%
Budget = $1,500
Cost per lead (platform) = $1,500 ÷ 100 = $15
Cost per additional lead = $1,500 ÷ 30 = $50
Where incrementality is often low
- Brand search: Many clicks come from people who would have searched for you anyway.
- Retargeting: The audience already knows you and was close to deciding.
- View-through conversions: They're credited without a click, and some of them would have happened without the ad.
Incrementality in lead generation
In lead generation, measuring incremental leads isn't enough. What matters is whether they turn into additional customers. If you evaluate a test on leads, check later in your CRM how many leads from the test period were qualified and closed.
Common mistakes
- Confusing attribution with impact: A high ROAS in the ad account doesn't mean the campaign brings a lot of additional revenue.
- Adding up platform numbers: Several platforms often credit themselves with the same conversions.
- Testing only once: Incrementality changes with budget, season and competition.
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Frequently asked questions
Guides on this topic
Articles on this topic
- Measuring Incrementality: Do Your Ads Really Bring Additional Leads?Google has opened Conversion Lift studies for Search and Performance Max without a Google rep. What incrementality means, why attribution doesn't show it and how to check it in lead generation, even with low volume.
- Meta Measures Conversions on Customer Devices: What Changes from November 12Meta is turning on a new pixel setting that matches conversions directly on users' devices. What it does, why it doesn't apply in the EU and UK, and what it means for leads and your reporting.
- Google Data Strength: What's Behind Tag Gateway and the New Uplift MetricGoogle is making data strength its key theme for 2026: a new Data Strength Uplift metric, Google tag gateway and Data Manager. What's behind it, how reliable the numbers are and what lead generation businesses should do.
- Meta Attribution in 2026: What Engage-Through Means and Why Conversions Are MissingSince March 2026, Meta only counts link clicks as clicks, while likes and saves count as engage-through. Two view windows are gone, too. What changed and how to read your numbers correctly.
Related terms
All termsConversion Lift · A control group test on the ad platform
A conversion lift test measures how many additional conversions a campaign brings by comparing a test group that sees ads with a control group that doesn't.
Attribution · Assigning conversions to marketing channels
Attribution assigns leads, purchases and revenue to the channels, campaigns and ads that drove them – the basis for every budget decision you make.
View-Through Conversion · A conversion after seeing an ad without clicking
A view-through conversion is a conversion credited to an ad because the user saw it but didn’t click it, and converted within the view window.
ROAS · Return on Ad Spend
ROAS (return on ad spend) measures how much revenue every dollar spent on advertising brings in: revenue from ads divided by ad spend.
Attribution Window · The time frame for crediting a conversion
An attribution window defines how many days after a click or view a conversion is still credited to an ad, for example 7 days after the click.
Customer Journey · The path from first contact to closed deal
The customer journey describes every step and touchpoint a prospect goes through, from the first contact with your brand to the purchase or signed deal.