3 Metrics to Measure the Health of Your Email Subscriber Base


Maintaining a healthy email subscriber base is critical to the success of any email marketing program. Issues with database health could lead to serious problems such as blacklisting, but also could mean you are losing traction with your email subscribers. Use these key metrics to help measure the health of your subscriber base.

Bounce Rate

Bounce rate tells you what percent of the messages you sent did not reach your subscribers’ inboxes. A high bounce rate may indicate that there are invalid email addresses in your subscriber base. To avoid being considered a spammer, it’s particularly important to track this metric on an ongoing basis. Also consider examining the difference between hard and soft bounces. A hard bounce is permanently undeliverable, whereas a soft bounce is only temporarily undeliverable. A deeper analysis into bounce types will give you more insightful and useful information.

Growth Rate

Increasing email subscriber base size is a common goal for many marketers. Make sure you are gaining more subscribers than you are losing to maintain a positive subscriber growth rate over time. If you are looking to increase the number of subscribers to your email program, think about using new tactics like encouraging customers to sign up for your emails in-store or offering a promotion for customers who subscribe online.

A few things can negatively impact your subscriber base growth. Besides number of unsubscribes, you should also look out for email addresses marked as dead (or undeliverable).

% Active versus % Inactive

Another metric you can use to measure the health of your database is analyzing what percent of your database is active versus inactive. If a large percentage of yoursubscriber base is inactive, your email marketing program may need to be optimized to boost engagement.

Every marketer is unique, so how activity is defined will vary from marketer to marketer. For example, some common behaviors to incorporate into your definition could include email engagement or purchase behavior over a given period of time (e.g. opened or clicked in the last 90 days, purchased in the last 30 days). While measuring what percent of your database is active at any given time can be helpful, you’ll get the most benefit from this metric by measuring it over time so you can identify trends.

Maintaining a healthy email subscriber base is just as important as measuring engagement like opens and clicks. Be sure to incorporate subscriber bounces, growth, and activity in your analytics toolkit to gain valuable insights and continue to drive your email marketing programs in the right direction. 

Author Bio

Yazmin Harris

Yazmin is currently an Analyst in Social & Disruptive Marketing Strategies, focusing on bringing innovation to the ESP space. Prior to joining Yesmail, she worked as a consultant with RR Donnelley in their direct mail division where she gained valuable experience in critically assessing client objectives in order to deliver viable marketing solutions. Yazmin has a B.A. in Statistics and a certificate in Integrated Marketing Communications from Northwestern University.