Prove the journey moved the metric

A measurement discipline that ties every automation to one outcome, defined before it ships — so "did it work" has a number instead of an anecdote.

When to run it

The journey has been live for a quarter, the send counts look healthy, and someone asks the only question that matters: did it work? If the answer starts with "well, opens are up", you have engagement numbers standing in for an outcome. For an agency this is existential — the retainer renews on proof, not on sends.

Why it works

The reason most journeys can't be defended is that the outcome was never defined as an event. "Improve retention" can't be measured; "a session.started within 14 days of the winback send" can. Naming the outcome event before shipping does two things: it forces the journey to have a falsifiable job, and it makes the measurement free — the conversion is a query over events you're already collecting, not a data project.

The play

1. For each journey, write the claim as an outcome within a window: trigger → result, e.g. payment failed → payment recovered within 7 days.
2. Ship the journey with a holdout — a slice of eligible users who enter nothing. This is the difference between "conversions happened" and "the journey caused them".
3. Read the three tiers honestly: touched (saw the journey), attributed (converted inside the window), incremental (lift over the holdout). Only the last one is allowed to say "caused".
4. Review monthly. Kill or rewrite journeys whose lift is indistinguishable from zero — a lifecycle system earns trust by deleting its own dead weight.

Ship it with Hogsend

The holdout is one line of journey meta; the engine assigns eligible users to the held-out cohort and the lift endpoint does the comparison.

import { days, defineJourney, hours } from "@hogsend/engine";

export const winbackMeasured = defineJourney({
  meta: {
    id: "dormant-user-winback",
    trigger: { event: "user.inactive_90d" },
    entryLimit: "once_per_period",
    entryPeriod: days(90),
    suppress: hours(0),
    // 10% of eligible users enter nothing — the control group.
    holdout: { percent: 10 },
  },
  run: async (user, ctx) => {
    // …the winback play, unchanged
  },
});

At low volume the lift report says "not enough data yet" instead of dressing noise in a percentage — the win probability is suppressed under 10 combined conversions. The full model — attribution windows, scoped credit, and the three claim tiers — is documented in conversions & impact, and cross-journey funnels covers measuring a sequence of journeys as one path.

How you'll know

This play's output is the knowing: a monthly one-pager per journey — trigger, outcome event, window, conversion rate, lift over holdout. The first time it kills a journey everyone assumed was working, it has paid for the setup.