A taxonomy that survives the third product manager

Naming is governance. A Birmingham payments app taught us that again when three owners in eighteen months each added a parallel word for “pay”.

By the time the third product manager arrived, the event stream contained payment_submitted, PayTapped, checkout_pay_click, and a property called success that meant three different things. None of the names were foolish in the week they were born. Together they made cohort work theatrical. Analysts spent Thursday morning deciding which name was in season.

The four-part rule

Event Taxonomy Studio uses a stubborn pattern: object, action, tense of completion, then properties that are not themselves events. listing_created is an event. is_draft is a property. Mixing them — an event called draft — is how a warehouse becomes folklore.

We forbid verbs that describe the interface. clicked_yellow_button dies when the button is no longer yellow. We forbid vendor souvenirs in the name. amplitude_experiment_exposed tells you the tool, not the behaviour. The constitution holds the vendor mapping in a column to the right, where it belongs.

Deprecation as etiquette

Teams hide old names because deletion feels violent. Hiding is worse. The old name continues to fire in a forgotten screen, quietly inflating a funnel. The ritual we teach is public: mark the name dead in the constitution, give it an end date, keep it in the warehouse with a deprecated_on column, and stop teaching it in onboarding. After ninety days of zero volume you may archive. You still do not reuse the string.

The Birmingham team deleted eighty-six names in a single afternoon once the ritual existed. Nobody outside analytics noticed, which is the point of a taxonomy that is not a branding exercise.

Who is allowed to add a name

If anyone can add an event, you do not have a taxonomy. You have a guestbook. We ask for a single steward — often a product analyst — and a weekly twenty-minute review. That is enough for a mid-size UK app. It is not enough for a bank. Banks need a written exception path, which is dull, and which is why their streams sometimes work.

The third product manager should be able to add a property without a meeting and should not be able to add an event without the steward. If that sentence offends a culture that prizes speed, the cost shows up later as a D7 nobody trusts. Choose the cost on purpose.

The longer version is taught in Event Taxonomy Studio. The Signal Atlas puts this work on Layer I, before anyone is allowed to argue about cohorts.