The Frame
DOOH doesn't replace digital advertising. It reaches the same audience in a different mental state — out in the world rather than behind a screen. The channel extension argument: digital competes with every other ad on the device. DOOH reaches the same person when they're not on a device, near purchase decisions, with no competing ads in their field of view.
Audience Overlap Is Not a Problem
A common objection: "aren't I reaching the same people I reach digitally?" Often yes. But reach overlap is different from attention overlap. Someone who sees your display ad while scrolling Instagram and your DOOH ad while fueling their car is the same person in completely different attentional states.
DPAA research shows multi-touchpoint campaigns including DOOH generate higher brand recall than single-channel campaigns at equivalent impression levels, even with underlying audience overlap.
Sequencing
Most effective pattern: DOOH runs 2–4 weeks first to build awareness, then digital retargeting activates to convert that awareness to action. DOOH plays the broadcast role (wide awareness, no click required). Digital plays the direct response role (targeted, action-oriented).
Critical: DOOH and digital creative should share visual DNA. A consumer seeing your OOH ad in the morning and your retargeting ad in the afternoon should experience them as one campaign.
Budget Allocation
No universal rule. Practical starting point: if digital is already running at scale in a market and marginal returns are diminishing (common above $50K/month), allocating 15–25% of digital budget to DOOH typically delivers positive incremental return.
For new market entry where brand awareness is low, start with higher DOOH allocation (30–40%) before scaling digital — you're building the recognition that makes targeting more effective.