The Kernel · 21 November 2025
When not to trust last click
Last click is a filing habit. It is excellent at producing a column in a spreadsheet and poor at describing how a person found an app in the United Kingdom in 2026, between walled gardens, delayed deep links, and a privacy prompt that ate the referrer.
Attribution Ledger is the sitting where we practise saying “we do not know” without using it as a shrug. The sentence has to be attached to a specific gap: no deterministic identity across web and app, overlapping paid and organic in the same hour, or an MMP window that credits a view nobody remembers.
Paid overlap is not a rounding error
When two networks claim the same install, last click simply picks the louder closer. That is a rule, not a measurement. We ask students to publish a dual view: claimed installs by network, and a capped “at most one” view that refuses to sum above 100% of new users. The second view is always smaller. Finance prefers it once they understand the first view was a duet.
Identity is a privilege
If you cannot join a logged-in customer across surfaces, you do not have multi-touch; you have folklore. The honest App Analytics move is to report on the surface you can actually observe and to keep brand search in a separate note rather than stuffing it into a model that needs an identity graph you do not operate.
One autumn letter rated the sitting 3.8 and asked for more MMP walkthrough. Fair. The chapter we will not shorten is the one that withholds credit when the graph will not support the claim. A budget meeting can survive an unfashionable sentence. It cannot survive a confident number that was only a habit.