Why last-click still runs your budget

Ask a Head of Growth which number they took into the last budget meeting. They will say last-click, or they will say data-driven and then, two slides later, last-click again. This is not stupidity. It is politics.

Last-click is a complete sentence. Paid Search closed it, so Paid Search gets the money. Everyone in the room already has a last-click report. The agency has one. Finance has one. The channel owner who is about to get cut has one. A black-box alternative that cannot be rebuilt on a whiteboard does not win that room.

In 2023 Google retired first-click, linear, position-based and time-decay from GA4 reporting. What remains is data-driven attribution and last-click. DDA is often better than last-click. It is also uninspectable. You cannot take the removal effect of Email to a CMO and show the paths. You can only say the model said so.

Path-level Markov and Shapley are inspectable. They require journeys. The GA4 Data API will not give you journeys. The BigQuery export will. That constraint is not a product preference — it is why most “GA4 attribution” tools are still last-click with nicer type.

A second opinion is useful when it disagrees in a way that is expensive. If last-click and Markov put Paid Search within two points of each other, you do not need a PDF. If last-click says Email is 8% and removal says 16%, you need a test, not a vibe. That is the whole product.

We still print last-click on page two. Hiding it makes you look like you are selling a fight. Showing it, with a delta and an interval, is how a CMO moves budget without pretending the agency is lying.