Ad Server Use-Cases: Ad Impression- and Viewability Measurement

[jurjendewal]

Problem:
As an advertiser I want independent, transparent and accurate measurement of my advertising activity.
Consistent and accurate measurement of advertising activity is critical for the internet as a marketplace where value is exchanged between publishers and advertisers and an important factor in the growth of advertising spending.

Impression measurement is a basic requirement for all brands and advertisers, either for direct IO buys with publishers or executed via a DSP.
Delivery and measurement of ad impressions is core functionality of creative ad servers who act as the single source of truth for reporting and procurement of brands and advertisers’ media activity.
In order to provide accurate measurement and transparency, ad servers are undertaking independent audits to have their measurement methodologies verified and accredited by the likes of MRC and IAB.

What is an ad impression?
Per MRC Desktop Display Impression Measurement Guidelines, an ad impression across all display marketing channels is the measurement of response from an ad delivery system to an ad request from the user’s browser, which is filtered for invalid traffic and is recorded at a point as late as possible in the process of delivery of the creative material to the user’s browser. The ad must be loaded and at minimum begin to render in order to count as a valid impressions. For simplicity we’re not considering mobile web, in-app and video impression measurement guidelines here.

What is a viewable ad impression?
Per MRC Viewable Ad Impression Measurement Guidelines , a served ad can be classified as viewable if the ad was contained in the viewable space of the browser window, on an in-focus tab, based on pre-established criteria such as percentage of ad pixels within the viewable space and length of time the ad is in the viewable space of the browser (a display impression can be classified as a viewable when 50% of the ad is in view for 1 second, for video its 50% and 2 seconds). It is recognized that an “opportunity to see” the ad exists with viewable impressions, which may not be the case with a served as impression.

From the several browser proposals and explainers it is not clear if the use case of event level impression measurement will be supported in the new “privacy by design” web.

There seems to be consensus around cross-domain identifiers, attributed data (Click Through Conversion Measurement – Chrome, Private click Measurement - Safari) and this Aggregate Reporting (API) for reach measurement, but the use case of event level impression measurement using on page JavaScript is not currently addressed.

Is the browsers’ intent to move impression and viewability measurement to browser (APIs) similar to IAB Tech Lab’s Open Measurement standard?
Such measurement would need to be adopted by all browsers universally in other to provide consistency to advertisers, brands and publishers and is fundamental to the ad funded open web.

If impression measurement would be done by the browser instead of the ad server, this would end independent measurement and transparency which is critical in an ecosystem controlled by few.

Will the browsers (like the walled gardens) allow independent auditing of their APIs and measurement methodologies to provide the transparency and assurance to the industry needs?
Will the browser control invalid traffic (IVT) filtration and adhere to the same standards and guidelines as set out by e.g. MRC and or work with these bodies to (re)set them?

The main question here is if the status quo of event-level impression measurement using on-page JS is a) untouched or b) a supported use case in the new privacy by design web?

[jurjendewal]

Important differentiation to make is Publisher Ad Servers (first party) vs. Creative Ad Servers (3rd party).
The use case above was written with creative ad servers / measurement vendors in mind. From the browser's comments (https://github.com/w3c/web-advertising/blob/master/support_for_advertising_use_cases.md) I can see this nuance was missed and I would welcome further feedback addressing both the publisher and marketer side.

[csharrison]

Hi, sorry for the delay here.

In general impression measurement only requires specialized APIs if it the thing being measured contains some cross site data (for conversions this is the join of the impression and conversion). For many use-cases that just want to measure impressions alone this is not the case, and you should be able to log impressions as you do normally with whatever methodology you like (to consider viewability etc).

The only time this would become a problem would be if ads are rendered in a special blind environment like the TURTLEDOVE proposal, where we would need some integration with aggregate reporting to count impressions.

cc @michaelkleber FYI