Retention, which measures how long users or users continue to use a product after their first purchase (or after they sign up or first log in), is vital to growing a customer base. If users aren't retained, any product---regardless of how fast its acquiring new users---will struggle to stay relevant.

The reports in this Playbook focus on understanding retention rates for your product. They describe how retention evolves over time, how it varies across different users groups, and how your retention rate affects the size of your user base. Finally, this Playbook helps you uncover which metrics are most predictive of user retention. Facebook famously found that users who became friends with at least 7 other people in 10 days become long-term users---for other products, one purchase, logging in three times in their first week, or sharing something on Twitter could all be important indicators. This Playbook helps you find these answers.

The Retention Playbook includes four reports you can tailor to your data. For an overview of how Mode Playbook reports work, please read this article.

• How do I calculate user retention and churn rate? Includes three charts that cohort users by the time period they first appeared, and shows how users of different age cohorts retain over time.
• How do I customize user cohorts to explore user retention? Investigate how retention relates to other cohorts, such as the day of the week that they signed up.
• Which user event correlates with user retention? Explore single user actions that most strongly correlate with retention.
• Which group of user events correlate with higher retention rates? Explore grouped user actions to find further retention insights.