List Decay Rate
The percentage of email subscribers who become inactive or unsubscribe over time, affecting email deliverability and engagement.
Definition
List decay rate measures how quickly email subscriber lists lose active, engaged contacts through unsubscribes, bounces, and natural audience turnover. Industry averages suggest 20-25% annual decay rates.
This metric impacts email deliverability, as internet service providers monitor engagement rates when determining inbox placement. High decay rates often indicate poor list management, irrelevant content, or inadequate subscriber acquisition strategies.
Why It Matters
Understanding list decay helps businesses plan subscriber acquisition needs and budget email marketing investments appropriately. Proactive list management prevents deliverability issues and maintains campaign effectiveness.
Companies with high decay rates often struggle with email ROI and sender reputation problems. Monitoring this metric enables timely intervention through re-engagement campaigns and list cleaning processes.
Examples in Practice
B2B newsletter: Software company tracks 22% annual subscriber loss and implements quarterly re-engagement campaigns to identify and remove inactive contacts.
Retail email list: Fashion brand notices 30% decay rate and discovers their weekly promotional emails are too frequent, leading to adjusted sending frequency.
Nonprofit organization: Charity experiences 40% decay after event season and creates targeted content series to re-engage lapsed donors and volunteers.