Even ROI can't be counted separately, as both companies can count the same conversion as theirs (up to 30 or 90 days layer if I recall correctly). You really need to use 3rd party for validation.
There's nothing I hate more than a viewthrough - media agency telling me they're responsible for hundreds of conversions when all they've done is put a banner on a webpage (usually combined with retargeting) that's in the viewport for a second.
Basically saying a non-guaranteed second of eyeball time in a banner-blind spot from someone they're retargeting who's already visited our site who converted 60 days later is their acquisition. [0]
I'm a marketer and I despise some of the crap these ad companies are selling.
[0] Conversely, this makes my personal KPIs look amazing, since I can take credit for other people's work and attribute it as my own. Obviously not doing that has caused me twice as much work to get proper attribution set up. If you want an easy life, push the BS metrics they give you.
I dunno, I like view-throughs. I can definitely remember viewing an ad and then converting many, many times so I regard it as pretty normal. I totally get where you're coming from with providers and attributions though :)
Yeah, on a more technical level, the issue I put to the agency was that they had the same weighting in their conversion reporting for a retargeted viewthrough as they did for a click through conversion from a source that was the only channel in a linear attribution.
The former is some nice data on steps to convert, the latter is a conversion driver - the problem is, the latter is hard and the former is easy, so ad tech agencies try and spin them as being equal since they want to push the easy "wins".
Yeah, that agency was talking bullshit. Sadly, all too common. I really wish Goog/ FB would get their shit together and allow proper measurement of them both, but it's not really in their interests to do so, sadly.