Your attribution model is the most consequential piece of fiction in your business and everyone who works closely with it knows it and nobody in the budget meeting says so.
Last-click attribution is a map that only records the final step of a journey that took eleven touchpoints and six weeks. Multi-touch is a more sophisticated guess that distributes credit according to a logic somebody agreed once and nobody has revisited. Both of them tell a story about which channels produced the revenue. Neither of them tells you which channels would have produced it anyway without the spend.
The incrementality question, whether the spend caused the revenue or whether the revenue was coming regardless, is the question that changes every budget allocation decision you will make this year. It is also the question that the standard attribution framework was not built to answer, because answering it honestly would require redistributing budget in ways that some channels and some agency relationships would not survive.
You are optimising inside a measurement system that is measuring the wrong thing clearly. That is not a technical problem. It is a governance one.
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