Frequency Optimization Depends on Engagement

As an email marketer, you spend a lot of time figuring out how your subscribers interact with your brand. However, this tells only part of the story. Unless you can see how your subscribers interact as a whole—with other brands as well as your own—you can’t make an accurate assessment of a subscriber’s engagement level.

By segregating your subscribers based on how they interact with email as a whole, you will be better equipped to judge their overall email frequency tolerance.

Three major types of accounts
For this study, we grouped subscribers into three categories based on Return Path’s panel:

  1. Primary: These accounts are actively engaged, meaning subscribers regularly show inbox activity like reading, deleting, and moving messages.
  2. Secondary: These accounts receive a high number of promotional and transactional messages, but few personal messages; subscribers are less engaged than Primary accounts.
  3. Dead: This group shows very little engagement with their inbox.

Why are these categories important?
Most marketers use engagement level as a basis for making decisions around send frequency. Best practices typically recommend sending more to engaged subscribers, as they’re less likely to complain, and sending less to disengaged subscribers because they tend to complain more, causing deliverability issues. In fact, our research found the exact opposite to be true.

Primary accounts are the most active as well as the most sensitive. These accounts belong to the “zero inbox” and power users. Email sent to these accounts are read and interacted with, accounting for 83% of all reads, but it also draws a surprising number of complaints. Primary inboxes account for roughly 24% of users among our panel, but generated 50% of all complaints.

Secondary accounts are moderately active, reading only a small percentage of email they receive. They may be “side” email accounts used for subscribing to promotions and checked only occasionally. These accounts make up 67% of all users in our panel, accounting for just 16% of total reads and approximately half of complaints.

Dead accounts were likely created and abandoned—not quite unknown users or spam traps yet, but well on their way. These accounts are rarely checked, let alone actively engaged. Dead accounts make up 9% of users in our panel and generate less than 1% of reads and complaints.


This breakdown provides three important takeaways related to email send frequency:

  1. Your most active and engaged subscribers are the most valuable, but they’re also the most sensitive—and the most likely to complain. Making changes to this group should be done cautiously, with the correct data and lots of testing.
  2. Secondary accounts, while technically an active inbox, are likely to be classified as inactive by some marketers. It’s difficult to make accurate decisions about send frequency and removal of inactives based on a typical dataset.
  3.  Complaints don’t come from where you’d expect. “Inactives” aren’t the biggest driver of complaints, and varying send frequency to this group—either more or less—isn’t likely to make a difference in complaints or opt-outs.

Want to learn more about sending frequency’s effect on your email program? Download our latest report, Frequency Matters: The keys to optimizing email send frequency.



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