Every Subscriber Has an Optimal Frequency

Basic math tells us that increasing email send frequency can lead to an increase in total reads. But what affect does frequency have on subscriber complaints? To observe the relationship between a high mailing frequency and subscriber complaints, we took a closer look at Primary accounts—described in my last post as the most engaged, economically valuable, and sensitive subscriber group.

For our recent report, Frequency Matters: The keys to optimizing email send frequency, we analyzed the sending frequency and engagement shifts from nine apparel companies where there was subscriber overlap. Additionally, we isolated senders that showed enough frequency variance to make our analysis valid. After normalizing the data based on this criteria, we were left with eight major retailers, and discovered a non-linear relationship between increased send frequency and increased complaints.

In simple terms, we found that engaged, Primary accounts will tolerate up to about five emails per week from a given sender. Beyond that, the ensuing complaints increase dramatically, and read rates drop significantly.


* Linear regression models the relationship between a set variable (send frequency) and an independent variable (read rate). The line represents the expected read rate for each increase in frequency, based on the available data.

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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