Glossary /
iROAS
Efficiency & cost
iROAS
The ROAS that only counts the revenue your ads actually caused — and it's lower than the number on your dashboard.
Attribution & Measurement
Unit Economics
Data Governance & Nomenclature
Creative & Delivery
Audiences & Targeting
Mobile & Privacy
iROAS (Incremental ROAS) is return on ad spend calculated using only incremental revenue — the revenue your ads genuinely caused — rather than all attributed revenue. It strips out conversions that would have happened anyway.
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What is iROAS?
Standard ROAS divides all attributed revenue by spend. The problem: much of that attributed revenue comes from people who would have bought regardless. iROAS fixes this by using only incremental revenue — measured through holdout or geo experiments — in the numerator. The result is sobering. iROAS is almost always far lower than platform-reported ROAS, often by 2x or more on channels that mostly intercept existing demand, like branded search or retargeting. That gap isn't a bug; it's the truth platform attribution hides. iROAS is the number that should drive budget decisions, because it answers what an incremental dollar of spend actually returns. A channel with a glamorous reported ROAS and a weak iROAS is quietly taking credit for sales you'd have made for free.
iROAS formula
iROAS = Incremental Revenue ÷ Ad Spend
iROAS = Incremental Revenue ÷ Ad Spend. The numerator is not total attributed revenue — it's only the revenue your ads genuinely caused, derived from an incrementality test (the lift measured against a control group). Spend stays the same; the revenue figure is the honest one.
Worked example
The same campaign, measured against a holdout.
Incremental Revenue
$30,000
Ad Spend
$10,000
iROAS
3.0x
$30,000 ÷ $10,000 = 3.0x
iROAS counts only revenue the ads actually caused, so it is typically far below the platform's reported ROAS.
iROAS formula
iROAS = Incremental Revenue ÷ Ad Spend
iROAS = Incremental Revenue ÷ Ad Spend. The numerator is not total attributed revenue — it's only the revenue your ads genuinely caused, derived from an incrementality test (the lift measured against a control group). Spend stays the same; the revenue figure is the honest one.
Worked example
The same campaign, measured against a holdout.
Incremental Revenue
$30,000
Ad Spend
$10,000
iROAS
3.0x
$30,000 ÷ $10,000 = 3.0x
iROAS counts only revenue the ads actually caused, so it is typically far below the platform's reported ROAS.
How iROAS differs across ad platforms
Meta
Meta reports ROAS from attributed conversions, which inflates the figure. To get iROAS you need a Conversion Lift study for the incremental revenue — and that study is still run and reported by Meta itself.
Google Ads
Google's conversion value and ROAS are attribution-based and lean high, especially on branded search. iROAS requires pairing spend with an independent incrementality read, not Google's default conversion column.
Independent incrementality testing
The only unbiased iROAS comes from incremental revenue measured outside the platform — via geo or holdout tests you control — then divided by spend. No ad seller has an incentive to hand you a low iROAS.
Common iROAS misconceptions
If reported ROAS is high, the channel is profitable.
A high reported ROAS can hide a weak iROAS. If most of that revenue would have happened anyway, you're paying to take credit for free sales. The incremental return is what determines whether the channel actually earns its budget.
iROAS and ROAS should be roughly the same.
They're usually far apart. iROAS is commonly half of reported ROAS or less, especially on demand-harvesting channels. A small gap is the exception; a large gap is the norm, and it's the whole reason to measure incrementally.
Related Terms
Frequently Asked Questions
What is iROAS in simple terms?
iROAS is how much revenue your ads actually generated for every dollar spent — counting only the sales the ads truly caused, not sales you'd have made anyway. It's the honest version of ROAS, and it's usually a lot smaller than the number platforms show you.
How is iROAS calculated?
Why does iROAS differ across ad platforms?
How does Clarisights report on iROAS?
Attribution & Measurement
Unit Economics
Data Governance & Nomenclature
Creative & Delivery
Audiences & Targeting
Mobile & Privacy
iROAS (Incremental ROAS) is return on ad spend calculated using only incremental revenue — the revenue your ads genuinely caused — rather than all attributed revenue. It strips out conversions that would have happened anyway.
?
?
What is iROAS?
Standard ROAS divides all attributed revenue by spend. The problem: much of that attributed revenue comes from people who would have bought regardless. iROAS fixes this by using only incremental revenue — measured through holdout or geo experiments — in the numerator. The result is sobering. iROAS is almost always far lower than platform-reported ROAS, often by 2x or more on channels that mostly intercept existing demand, like branded search or retargeting. That gap isn't a bug; it's the truth platform attribution hides. iROAS is the number that should drive budget decisions, because it answers what an incremental dollar of spend actually returns. A channel with a glamorous reported ROAS and a weak iROAS is quietly taking credit for sales you'd have made for free.
iROAS formula
iROAS = Incremental Revenue ÷ Ad Spend
iROAS = Incremental Revenue ÷ Ad Spend. The numerator is not total attributed revenue — it's only the revenue your ads genuinely caused, derived from an incrementality test (the lift measured against a control group). Spend stays the same; the revenue figure is the honest one.
Worked example
The same campaign, measured against a holdout.
Incremental Revenue
$30,000
Ad Spend
$10,000
iROAS
3.0x
$30,000 ÷ $10,000 = 3.0x
iROAS counts only revenue the ads actually caused, so it is typically far below the platform's reported ROAS.
How iROAS differs across ad platforms
Meta
Meta reports ROAS from attributed conversions, which inflates the figure. To get iROAS you need a Conversion Lift study for the incremental revenue — and that study is still run and reported by Meta itself.
Google Ads
Google's conversion value and ROAS are attribution-based and lean high, especially on branded search. iROAS requires pairing spend with an independent incrementality read, not Google's default conversion column.
Independent incrementality testing
The only unbiased iROAS comes from incremental revenue measured outside the platform — via geo or holdout tests you control — then divided by spend. No ad seller has an incentive to hand you a low iROAS.
Common iROAS misconceptions
If reported ROAS is high, the channel is profitable.
A high reported ROAS can hide a weak iROAS. If most of that revenue would have happened anyway, you're paying to take credit for free sales. The incremental return is what determines whether the channel actually earns its budget.
iROAS and ROAS should be roughly the same.
They're usually far apart. iROAS is commonly half of reported ROAS or less, especially on demand-harvesting channels. A small gap is the exception; a large gap is the norm, and it's the whole reason to measure incrementally.
Frequently Asked Questions
What is iROAS in simple terms?
iROAS is how much revenue your ads actually generated for every dollar spent — counting only the sales the ads truly caused, not sales you'd have made anyway. It's the honest version of ROAS, and it's usually a lot smaller than the number platforms show you.
How is iROAS calculated?
Why does iROAS differ across ad platforms?
How does Clarisights report on iROAS?
See Viewable Impression across every channel in one report
See Viewable Impression across every channel in one report
See viewability and vCPM across every platform—display, video, programmatic— in one normalized report, instead of reconciling vendor numbers by hand.
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