Re: [private-measurement] Interoperable Private Attribution (IPA) (#9)

> I agree if we're talking about a cheater using information from site A to impact something about site B. However, if site A is willing to give a "cheater" ability to execute JS on their site, how we can prevent anything beyond that.

Great point. There might be some nuance here with iframes, but even still there is a detection problem that we should think through. This goes back to the general problem of supporting multiple separate reporting origins though which we should flesh out. It ends up being a complicated coordination problem (and possible denial-of-service vector) if everyone has to share a single budget. Needing to involve the advertiser in it makes this even tougher.

One more question about IPA behavior. I want to confirm that attribution across multiple queries works correctly. Here's an example: imagine there's a single advertiser selling a single product, and is running 3 different campaigns for it. They want to use IPA to measure the relative performance of their 3 campaigns. This is my understanding of how this would work in IPA.

The advertiser will send 3 queries to the system:
1. {Campaign1's source events, all trigger events}
2. {Campaign2's source events, all trigger events}
3. {Campaign3's source events, all trigger events}

If IPA treats these queries completely independently, then attribution does not take into account source events from separate queries. That is, a hypothetical user journey like {Campaign1 source event, Campaign2 source event, Campaign 3 source event, trigger} will end up contributing a count to each of the three queries above, causing double counting.

One way to make this work would be to first run "global attribution" with the union of the events in all the queries, and then separately evaluate each query separately from the pool of globally attributed sources/triggers. I couldn't tell if this was how the protocol was intended to work though.

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Received on Saturday, 7 May 2022 20:03:04 UTC