For digital OOH, we cannot assume that the media being tracked was "always-on", since digital OOH changes the ad being displayed after a certain amount of time. In contrast to static OOH, which is always showing the media we are tracking, we must take into account the time that a particular ad played.

Therefore, in order to properly perform attribution on a campaign with digital OOH, we must receive ad roll logs from each vendor on the plan.

Not Proof of Plays

First, a description of ad roll logs are not. This is not equivalent to proof of play logs. Proof of play logs (POPs) are a common report produced by vendors in order to demonstrate to their customers that the order is being fulfilled. These are generally rolled-up, i.e. aggregated views of the underlying log data. A typical POP might look something like

This tells us how many times the ad roll in a given hour for a given unit. However, it does not tell us the specific times the ad rolled at for each unit. What we need to understand is, for each unit, what the exact time the campaign rolled.

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No Aggregation, Please!

POP logs take underlying log data, group by certain fields such as Unit ID and hour, and report the count of the number of rolls in that period.

Ad logs report the exact time an ad rolled!

Ad Log Format

Ad logs must be self-contained: one file in which every row carries both the ad play and the unit it played on. A row is a single play, and it says everything needed to place that play in space and time without reference to any other file.

Required fields:

• timestamp - well-formed timestamp with unambiguous timezone. This usually refers to the start of the ad roll.
• latitude - latitude of the OOH unit
• longitude - longitude of the OOH unit
• unit_id - unique identifier of the OOH unit
• duration or end_timestamp - duration of the ad roll in seconds, or the time the ad stopped playing

Optional fields:

• facing - direction the unit is facing
• additional cut fields relating to either the unit or the play, such as market, format, creative_name, or media_id

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Split Files Are Not Supported

Some vendors offer ad logs as two files - a unit list and a separate play log joined on unit ID. Mira does not accept that format. Ask the vendor to join them before delivery, so that each row of the file you send carries its own coordinates.

Ad Log Checklist

Operators should request a sample of ad logs from vendors. Here is a quick guide to check samples:

• Ensure there is no aggregation present
  • A tell-tale sign is if there is a computed column like "total plays", or if the time resolution is anything less than second-resolution.
• Ensure timestamp is well-formed, and that the timezone is unambiguous
• Ensure there is an end timestamp, or an ad roll duration field
• Ensure cut fields are present
• Ensure the log covers the entire buy, not a subset of units
  • This usually must be checked by asking the vendor, as the sample might be obtained before the campaign is live