What is marketing incrementality?
By Harry Burman · Updated October 20, 2026
Marketing incrementality is the extra sales caused by marketing spend: sales with the ads minus the sales you would have had without them. Platform reports count credit. A holdout test estimates cause, which is what the budget decision needs.
Marketing incrementality is incrementality applied to paid media: the sales that would not have happened without the marketing spend you are evaluating. It is the same idea as incrementality in general, focused on ad dollars rather than any activity that might move sales. Meta, Google and Amazon Ads report attributed revenue under their own windows; those numbers mix buyers who would have ordered anyway with buyers the ads moved, and they miss paths platforms cannot see, such as Meta creative that leads to Amazon brand search. To estimate it you need a holdout of people or places, or a model checked by tests. For Amazon brands on Meta, a geo holdout that pauses ads in matched states and compares Amazon ship-to orders is the usual design. Divide caused sales by spend for incremental ROAS and compare that to break-even after fees. Size the test with the holdout calculator first.
Marketing incrementality vs. incrementality
Incrementality is the broader term: the sales an activity causes. Marketing incrementality narrows that to marketing spend, usually paid ads you can turn up, down or off. Organic search, PR and word of mouth can be incremental too, but this page is about the budget question: what did these ad dollars cause?
marketing incrementality = sales with the spend − sales without the spend incremental ROAS = marketing incrementality ÷ ad spend
You never observe both sides for the same people at once. Every measurement method estimates the missing "without" line. The extra orders are incremental sales; in dollars they are incremental revenue.
Not the same as attributed marketing results
Attribution answers "who got credit?" Marketing incrementality answers "what changed because of the spend?" A campaign can look strong in Ads Manager and still be flat in a holdout, or look weak on Amazon Attribution and still move ship-to orders.
- Over-credit. Retargeting reaches people already about to buy; credit counts them as ad-driven.
- Under-credit. Someone sees Instagram creative, skips the click, and searches your brand on Amazon. Neither Meta nor Amazon Attribution sees that path clearly.
Gordon and others (2019) compared large Facebook experiments with common non-experimental methods and found those methods often misstated the effect.
A made-up spend example
A brand spends $10,000 on Meta in a month. Ads Manager credits $45,000 (reported ROAS 4.5). A geo holdout finds about $22,000 of caused Amazon revenue (incremental ROAS 2.2). The marketing incrementality figure is the $22,000, not the $45,000.
Put your own lift into dollars with the incremental ROAS calculator, and check whether that clears break-even after product cost and Amazon fees.
How to measure marketing incrementality
You need a holdout group: people or places that do not see the ads but are otherwise alike.
- User holdouts inside Meta measure purchases Meta can track. They miss most Amazon checkouts.
- Geo holdouts pause ads in matched regions and compare Amazon orders by ship-to state. That is the usual path for Meta → Amazon brands. See geo testing and incrementality measurement.
Size the design with the holdout test calculator before you pause spend. The math and design rules are on how lift is calculated.
Where Spillmark fits
Spillmark runs geo holdout tests for Amazon brands that spend on Meta. It plans matched regions from your order history, locks the design before the test starts, measures what your Meta ads cause on Amazon, and reports the range around lift so you can compare incremental ROAS to break-even.
Frequently asked questions
What is marketing incrementality?
The sales caused by marketing spend: sales with the ads minus the sales you would have had without them. It is incrementality applied to paid media, not platform credit.
How is marketing incrementality different from incrementality?
Incrementality is the general idea of caused sales. Marketing incrementality focuses on ad or media spend you control with a budget.
Is marketing incrementality the same as ROAS?
No. Reported ROAS uses credited revenue. Marketing incrementality uses caused sales; divide those by spend for incremental ROAS (iROAS).
How do Amazon brands measure marketing incrementality on Meta?
With a geo holdout: pause Meta in matched states, keep ads on elsewhere, compare Amazon ship-to orders, and report a range around the lift.
Can I measure marketing incrementality without a test?
Models such as marketing mix models can estimate it from history, but they work best when holdout tests check them. A holdout is the direct measure.
Sources
- Gordon, Zettelmeyer, Bhargava & Chapsky, A Comparison of Approaches to Advertising Measurement: Evidence from Big Field Experiments at Facebook (Marketing Science, 2019)
- Lewis & Rao, The Unfavorable Economics of Measuring the Returns to Advertising (Quarterly Journal of Economics, 2015)
- Vaver & Koehler, Measuring Ad Effectiveness Using Geo Experiments (Google, 2011)
- GeoLift, Meta's open-source geo experiment package