OOH / DOOH measurement
Traffic, OTS, LTS, Reach, Frequency, GRP and other metrics — with formulas, examples and guidance on correct interpretation.
Start with the essentials↗Each successive layer narrows the raw flow and makes the metric more meaningful. Skipping a layer changes the question the result actually answers.
Side, format, operating mode
Geometry and obstructions
Route and speed
Contact at the relevant moment
Qualified contacts
Deduplication and projection
Reach and intensity
Relative media weight
Raw flows become the audience of a specific campaign only after accounting for the surface, visibility, ad-serving time, contact qualification, deduplication and projection.
Dates and time window
Market, city, zone
Audience base and filters
OTS, LTS or Audience
Surface, spot, campaign
SOV, loop, uptime, PoP
Deduplication and projection
A hypothetical campaign helps show the formulas within one consistent framework. The figures below are not data from a real placement.
If LTS in the same example equals 420,000, the corresponding LTS-Reach, LTS-Frequency and LTS-GRP must be recalculated on that same base — they cannot be mixed with OTS-based metrics.
Definition, question, calculation, example, limitations, common mistake, required context and how the metric is used in METER.
Core definition
Traffic shows the number of people, vehicles or devices near a location. Audience is established only after movement is linked to a specific surface, ad-serving time, visibility zone, contact rules and deduplication.
How much movement was observed near the location, and what share of it could qualify as a candidate advertising contact?
10,000 vehicles passed along the road. That is 10,000 traffic events, not 10,000 people and not 10,000 advertising contacts.
Applying one universal coefficient to gross traffic and calling the result an audience.
In METER, mobility data goes through quality control and route reconstruction. Raw geosignals do not become an audience until contact qualification, deduplication, weighting and projection are applied.
Core definition
Universe is the predefined population against which Reach, Rating, GRP and TRP are calculated. It must match the geography, period and selected audience used in the report.
Which population or target segment is the metric calculated against?
A Reach of 300,000 against a Universe of 1,000,000 equals 30%. The same audience against a Universe of 600,000 would equal 50%.
Comparing two Reach percentages without checking whether geography, age, period and target group are defined consistently.
In METER reports, the selected audience filters define the Universe being analyzed. Panel observations are scaled to that Universe after statistical weights are applied.
Core definition
OTS is the estimated number of potentially viewable contacts over a selected period. One person can generate multiple OTS, so it is a gross contact metric, not a count of unique people.
How many qualified opportunities for contact did the surface or campaign generate?
One person qualified through the visibility zone five times: 5 OTS, but only 1 person in Reach 1+.
Reading 1,000,000 OTS as one million people or confirmed views.
METER calculates OTS after data quality checks, movement reconstruction, surface modeling and contact-session qualification.
Core definition
LTS refines OTS using available visibility, movement and campaign parameters. In the METER methodology, LTS cannot exceed OTS and is not described as a confirmed view unless gaze direction has been directly observed.
What share of potential contacts had a higher likelihood of seeing the message?
Out of 600,000 OTS, 420,000 LTS remained after accounting for geometry, exposure time and campaign parameters. This is an illustrative example, not a universal coefficient.
Applying one fixed LTS percentage to every surface, city and period.
For each surface, METER accounts for its individual visibility zone, direction and speed of movement, distance, angle and available campaign parameters.
Core definition
Reach 1+ shows the number or share of different people with at least one qualified contact. Reach N+ includes only people with N or more contacts.
How broad was the reach, and how many people received repeat exposure?
300,000 different people against a Universe of 1,000,000 gives Reach 1+ = 30%. If 120,000 received at least three contacts, Reach 3+ = 12%.
Comparing weekly and monthly Reach without accounting for duration, or adding the Reach of individual surfaces together.
METER combines a panel participant’s contacts, accounts for overlaps across surfaces and days, then projects the unique audience to the selected Universe.
Core definition
Frequency is the average number of qualified contacts per person already reached. The average does not show how evenly contacts were distributed across people.
How many contacts did each reached person receive on average?
600,000 OTS with OTS-Reach of 300,000 gives an average OTS-Frequency of 2.
Treating an average of 4 as proof that every person received exactly four contacts.
METER reports Frequency alongside Reach 1+/N+ and can diagnose a narrow overexposed core or insufficient repeat contacts.
Core definition
GRP applies to the full selected audience, while TRP applies to a predefined target group. These metrics can be used to compare media weight only when Universe, period and contact base are defined consistently.
What is the relative weight of campaign contacts within the total or target audience?
30% Reach × Frequency 2 = 60 GRP. 100 GRP can mean 50% × 2 or 25% × 4.
Comparing OTS-GRP with LTS-GRP, or two TRPs calculated against different target Universes.
In METER, audience filters define the target Universe. Reports should be checked for gender, age, income, geography, period and whether the metric base is labeled OTS or LTS.
Core definition
Deduplication prevents the same person from being counted more than once when they contact multiple surfaces, on different days or across different sections of a route.
How many unique people were reached after overlaps were removed?
Screen A — 100,000; screen B — 80,000; overlap — 50,000. Campaign Reach = 130,000, not 180,000.
Adding the audiences of all screens together and reporting the sum as campaign Reach.
METER combines contacts at panel level before applying weights and projection. Moving from an observed device to a person estimate is a modeling step and should be disclosed.
Each diagram addresses one common mistake and can be used independently in a presentation or publication.
You cannot jump directly from nearby movement to the audience of a campaign.
The numerator and Reach must be calculated on the same base.
High Reach 1+ does not guarantee sufficient repeat exposure.
Campaign Reach: 100k + 80k − 50k = 130k.
100 GRP does not mean 100% population reach.
Visibility describes physical opportunity, not attention.
Search by the English term, filter by topic, and use a permanent link to a specific definition.
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Inventory and audience
Outdoor advertising and other advertising formats outside the home.
#oohDigital outdoor advertising on screens with programmable playback.
#doohAn individual advertising surface or inventory unit. A side of a structure is treated separately if it has its own orientation.
#surface-assetThe set of placements for a specific advertising message within a defined period, geography and set of conditions.
#campaignThe population against which Reach, Rating, GRP and TRP are calculated.
Full definition →A deduplicated and qualified set of people defined on a disclosed methodological basis.
Full definition →Visibility and contact
The number of people or vehicles near a location. This is the raw flow, not yet the advertising audience.
Full definition →The physical area within which there is an opportunity to see a specific surface when visibility conditions are met.
#display-exposure-zoneA modeled visibility zone for a surface, accounting for geometry and available obstructions.
#viewshedA combined episode of a participant being present in the zone: multiple closely spaced signals do not become separate contacts.
#contact-sessionAn individual unit of advertising contact on the selected base. It may be a repeat contact for the same person.
#impression-contactAn estimated opportunity to see the message; a gross metric of potential contacts.
Full definition →A refined estimate of contacts with a higher likelihood of seeing the message; it is not the same as a confirmed gaze.
Full definition →The fact or probability of attention being directed at the ad; a separate measurement layer after visibility.
#attentionReach, frequency and media weight
The number or share of different people with one or more qualified contacts.
Full definition →The number or share of different people with N or more contacts.
Full definition →The average number of contacts per person within the reached audience.
Full definition →Distribution of the reached audience by number of contacts.
Full definition →Contacts or reach expressed as a share of the relevant Universe.
#ratingTotal media weight relative to the full selected audience.
Full definition →Total media weight relative to a predefined target audience.
Full definition →Preventing repeat counting of the same person when calculating unique reach.
Full definition →Delivery and verification
The share of advertising time or loop allocated to a specific campaign.
#sovThe full sequence of spots on a digital surface before the sequence repeats.
#loopAn individual advertising spot or creative asset.
#spot-creativeThe share of time during which the surface was operational and able to display advertising.
#uptimeVerifiable evidence that a creative was played or displayed; not proof that a person viewed it.
#proof-of-playVerification of whether placement occurred, during the correct period and under the agreed conditions.
#verificationEstimation of advertising contacts, unique audience, frequency and related metrics.
#measurementStages and calculations
Forecast-based assessment before placement.
#pre-buyOngoing monitoring of delivery, inventory operation and available audience signals.
#during-campaignFinal assessment of the campaign as actually delivered.
#post-buyA stable research sample of observed participants that meet the required quality criteria.
#panelA coefficient indicating what share of the population a panel participant represents.
#statistical-weightScaling panel results to the selected Universe.
#projectionAfter contact
Time spent in the zone that is relevant to the opportunity for contact.
#dwell-timeA point or polygon of interest: store, restaurant, office, transport hub, etc.
#poiVisits to a location; by itself, footfall does not prove an advertising contact.
#footfallAssessment of the relationship between an advertising contact and a subsequent action.
#attributionThe additional outcome that would not have occurred without the campaign; requires a control comparison.
#incrementalityReach, % = Reach 1+ / Universe × 100
Frequency = contacts / Reach 1+
GRP = Reach, % × Frequency
Key definitions, formulas, one example and five checks before comparing numbers. Suitable for meetings, email follow-ups and quick client responses.
Download PDF · A4↓This material explains the measurement methodology and does not constitute a claim of MRC accreditation, WOO certification or independent audit of METER. Numerical examples without a cited study are illustrative.