How Blindspot measures DOOH delivery

Out-of-home has never had one agreed way of counting itself. The IAB only published its Digital Out-Of-Home Measurement Guide in July 2025, and much of it is concerned with moving the category off blunt opportunity-to-see counting toward viewability-adjusted impressions and a shared foundation buyers and sellers can both use. Until that settles, the honest thing a vendor can do is state its own method plainly and let anyone check a report against it. This page is that statement.

Play

One display of one creative on one screen. It is the unit media is bought and billed on, and the unit every delivery figure in a Blindspot report counts. A play is not an impression and it is not a person.

Proof of play

The record a screen network writes when a creative is actually displayed. Each record ties one play to one screen at one moment, carrying a latitude, a longitude and a timestamp. Proof of play is what separates verified delivery from an estimate.

Reach

A count of people, compiled from operator audience figures for the booked screens. Reach is not counted from the proof-of-play log and is never added to a play count.

Daypart

A named window of the day that media is bought against, rather than buying the whole clock. Leaving a window unbought is a deliberate decision and shows in the log as zero delivery.

Average cost per play

Total media cost divided by verified plays delivered. It is the metric Blindspot reports on, because it moves when delivery moves and it can be checked against the log.

Dark day

A campaign day on which a booked screen did not run. Uptime is reported as days live against days booked, and dark days are reported even when a contract does not require it.

From a screen lighting up to a number in a report

A play is written to the log at the moment the screen displays the creative, not when the plan said it should. The log is reconciled weekly against operator certificates, and the export a client receives is a snapshot of that log taken after the flight closes. Every figure in a Blindspot case study is either counted directly from that export or derived from figures that are, and where a number is derived the derivation is shown next to it.

What this method does not tell you

A measurement page that only lists strengths is marketing. These are the real limits.

Plays are not people. A play proves a screen displayed a creative. It does not prove anyone looked at it. That is why plays and reach are reported separately and never summed.

Reach is an operator figure, not our count. Audience numbers for a screen come from the network that owns it, compiled to their methodology rather than ours. We report reach because clients ask for it, and we label its source every time.

There is no attribution here. Proof of play answers what ran, where and when. It does not answer who then booked a trip. Any claim connecting DOOH delivery to a downstream action needs separate measurement, and we do not make that claim from this data.

Panels and footfall studies are a different instrument. Blindspot does not report panel estimates. Where a campaign report carries footfall or engagement observations, those come from the operator or the client and are attributed to them.

How to audit a Blindspot number without taking our word for it

Ask for the export date and the flight window, then check the report only claims delivery inside it. Ask how many records the export holds and check that it equals the headline play count. Ask which figures are counted and which are derived. Ask what the contract required, because delivery against a contractual threshold means more than delivery against nothing. For a worked example, the Maharashtra Tourism worldwide campaign publishes its export date, its record count, its contractual KPI thresholds and the derivation behind every derived figure.