Definition
Cohort analysis is a method of grouping subscribers by a shared characteristic, such as the month they signed up, and then tracking their behavior over time. In email marketing, it is used to understand how different groups of subscribers engage, retain and convert after joining.
Instead of looking at aggregate metrics, which can hide trends, cohort analysis reveals whether newer subscribers are more or less engaged than older ones. It can show whether a change in signup source, welcome series or product offering is improving or worsening long-term performance.
For example, subscribers who joined in January might have a higher 90-day retention rate than those who joined in March, indicating a problem with the March signup source or onboarding experience. Cohort analysis turns these patterns into actionable insights.
Best Practices
- Group cohorts by meaningful attributes, such as signup month, source, segment or first purchase.
- Track retention, engagement and revenue over consistent time intervals.
- Compare cohorts to identify which acquisition sources produce the best subscribers.
- Use cohort insights to optimise onboarding, welcome series and first-purchase campaigns.
- Visualise cohort data in tables or heatmaps to make trends easier to spot.
Related Glossary Terms
A/B Testing
A/B testing in email marketing is the practice of sending two variations of an email to a small sample of your list to determine which version performs better before sending the winner to the remaining subscribers.
Abandoned Cart Email
An abandoned cart email is an automated message sent to customers who added items to their online shopping cart but left without completing the purchase. It is one of the highest-converting email types in ecommerce.
Abuse Complaint
An abuse complaint is a report from a recipient who marks an email as spam, which negatively affects sender reputation and deliverability.
ARPU (Average Revenue Per User)
ARPU (Average Revenue Per User) is a metric that measures the average revenue generated per email subscriber over a specific period, used to evaluate list value and campaign effectiveness.
Attention Rate
Attention rate is the percentage of email opens that last longer than 5 seconds, distinguishing genuine reads from passive opens, preview-pane views, or Apple MPP auto-loads.
Average Order Value in Email
Average order value in email is the average amount spent per transaction from recipients who clicked through from an email campaign.
Frequently Asked Questions
A cohort is a group of subscribers who share a common characteristic, such as signing up in the same month or from the same source.
It shows how different groups of subscribers behave over time, revealing whether changes in acquisition, onboarding or content improve retention.
Common metrics include retention rate, open rate, click rate, conversion rate, revenue per subscriber and lifetime value.
Segmentation divides your list for targeting. Cohort analysis tracks groups over time to understand trends and performance patterns.
Monthly or quarterly is usually enough. Review cohorts after major changes, such as a new signup flow or welcome series.