incremental ROAS
Return on ad spend measurement for incremental campaigns.
Frequently Asked Questions
What is Incremental ROAS (iROAS)?
Incremental Return on Ad Spend (iROAS) is a marketing metric that measures the **additional revenue** generated by an advertising campaign that would not have occurred without that specific ad spend. Unlike standard ROAS, which simply divides total revenue by ad spend, iROAS focuses on the **causal impact** of the advertising. It is the gold standard for determining the true effectiveness and profitability of a marketing channel, especially in a privacy-first world where platform-reported metrics are often inflated. iROAS helps marketers understand if their ad dollars are genuinely driving new sales or merely taking credit for conversions that were already going to happen.
How do marketers practically measure and calculate Incremental ROAS?
Marketers primarily measure Incremental ROAS through **incrementality testing**, such as A/B split tests, geo-lift tests, or holdout groups. The most common method involves comparing a test group that is exposed to the ads with a control group that is deliberately held out from seeing the ads. The formula for iROAS is: **(Incremental Revenue) / (Ad Spend)**. Incremental Revenue is calculated as the difference in revenue between the test group and the control group. For example, if the test group generates $10,000 more in revenue than the control group, and the ad spend was $2,000, the iROAS is 5.0. This practical measurement ensures that every dollar spent is directly contributing to business growth.
What is the difference between Incremental ROAS and Blended ROAS?
The key difference lies in what each metric measures: **causality vs. totality**. **Incremental ROAS (iROAS)** measures the *causal* impact of a specific ad campaign by isolating the revenue that would not have existed without it. It is a precise, campaign-level metric used for budget allocation and optimization. **Blended ROAS** (or Total ROAS) is a high-level, *aggregate* metric that divides a company's total revenue (from all sources, including organic, direct, and paid) by its total ad spend across all channels. Blended ROAS provides a holistic view of overall business health, but it cannot tell a marketer which specific channel is driving new customers, which is the sole purpose of iROAS.
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