The agency that built your attribution model also benefits from the conclusions it produces. I want to name that clearly because it is the most significant conflict of interest in the ecommerce industry and it is almost never described as such.
Your performance agency manages your paid channels. They also built or substantially influenced the measurement framework that evaluates those channels. The model assigns credit for revenue to the touchpoints that are visible to the agency and weighted in a way that was agreed during onboarding and has not been independently reviewed since.
When that model consistently shows that the channels the agency manages are driving strong commercial returns, the question worth asking is not whether the reporting is accurate. It is whether the reporting was designed to be accurate or designed to be defensible. Those are different objectives and the incentive structure of the agency relationship produces one of them more reliably than the other.
I am not accusing agencies of dishonesty. I am describing a structural reality that exists regardless of the intentions of the people inside it. A measurement framework built and managed by the party being measured is not an independent assessment. It is a grade given to homework by the person who wrote it.
Ask for the incrementality data. Watch what happens next.
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