Third-party Reporting on Non-Targetable Verification Segments / Browser Interest Groups

[jmarcusp3]

Use Case
Independent verification & transparency are common and necessary requirements in digital advertising. According to the World Federation of Advertisers Sep 2020 Cross-Media Measurement Technical Blueprint, advertisers foundationally require the ability to report on basic_segments (link) which must be independently verified. Stated concretely, browsers should have the ability to report on some strict list of basic_segments (i.e. cohorts / interest groups) that were not necessarily targeted.

The current aggregate reporting api alludes to the ability to for demographic slices to be reported upon (as indicated in the snippet below)

const entryHandle = window.writeOnlyReport.get('campaign-123');

// Add any demographic slices you want or know in the current
// context.
entryHandle.set('country', 'usa');

One could imagine the following:

entryHandle.set('basic_segment', 'age' , 'gender');

...however, the way in which this use case would be achieved is not entirely clear as basic_segments should be non-targetable class of browser Interest Groups.

Proposal
Advertisers and/or publishers should have an option for enabling verification basic_segment reporting. Perhaps this could be accomplished via an extension to the .joinInterestGroup() API, thus allowing verification companies to execute JS that adds basic_segment metadata to the browser:

const verificationGroup = {'owner': 'https://first-verification-company.com',
                 'basic_segment': {'age' : '18-24', 'gender': 'F'},
                };
window.navigator.joinAdInterestGroup(verificationGroup, 30 * kSecsPerDay);

This should allow for demographic reporting similar to the following:

{
 'entryName': 'campaign-123',
 'country': 'usa',
 'age': 18-24',
 'gender': 'F',
 'visits': '1'
}

The generic nature of a basic_segment makes these attributes well-disposed to being differentially private aggregations. Once this data is collected server-side some service can/should ensure that necessary privacy thresholds are met before releasing any aggregates for reporting (as already indicated in the Aggregation Service proposal).

The aggregated data should be forwarded to some .well-known location of the third-party verification company, when basic_segment verification reporting is requested by the publisher and/or advertiser.

Please let me know if this is unclear in any way!

[jmarcusp3]

Hi @csharrison is this an actively maintained proposal? I haven’t seen much activity across this repo, so wanted to confirm whether I should expect any commentary on this issue. Thanks!