Resurrection and Win-Back

By the end of this lesson, you should be able to: define a resurrected user, explain why resurrection grows in importance as a product matures, measure it with the right rate, and tell whether a win-back campaign actually brought people back.

What resurrection is

A resurrected user is someone who used the product before, was gone long enough to count as churned, and then came back.

So resurrection depends on your churn definition from the last lesson. Duolingo, for example, defines resurrected users as learners who are active today and were last active more than 30 days ago.1 That lines up exactly with its definition of dormant users, who have been inactive for at least 30 days.

Duolingo also separates a softer case. Reactivated users are people active today who were active in the past month but not the past week.1 They drifted, but not for long. Splitting the two helps, because someone back after ten days and someone back after a year are in very different situations.

Why resurrection matters more over time

Every user who churns joins a pool of past users. And that pool only grows.

Think about a product that's been around for five years. Every month, some users go dormant and join the pool. After five years, the pool of people who once used the product can be several times larger than the number of people using it today.

That changes the math of growth. Even if only a small share of the dormant pool comes back each month, a small share of a huge pool can be a lot of people. Social Capital, for example, counts resurrected users as one of the three parts of user growth, right next to new and churned.2