ROAS (Return on Ad Spend)

Return on ad spend (ROAS) is revenue attributable to a campaign divided by ad spend, usually expressed as a ratio (4:1 = $4 of revenue per $1 of ad spend). It's the inverse framing of CPA — same arithmetic, different denominator — and preferred when revenue per conversion is variable (e-commerce, B2B SaaS) rather than fixed (subscription sign-ups).

A 4:1 ROAS is roughly the rule-of-thumb breakeven for direct-response campaigns once production cost, agency fees, and the cost of goods sold are factored in. Anything above 4:1 is meaningfully profitable; sub-2:1 is loss-making at scale. Brand-building campaigns aim for lower ROAS thresholds in the short term and longer attribution windows.

For DOOH specifically, ROAS requires a stable attribution model — typically a cross-device match from screen-exposed household to online or in-store conversion. Magna's 2025 benchmark shows median DOOH ROAS comparable to display in CPG verticals when the attribution window stretches to 14 days post-exposure (vs. 1-day for click-driven channels).

Buyers should pay attention to the ROAS attribution window: a 1-day ROAS is structurally biased toward click channels; a 30-day ROAS shifts credit toward upper-funnel touches like DOOH and CTV. The right window depends on the buying-cycle length for the product.