The Myth of the Ignored Email

For brands, unread emails were long seen as dead weight—until Microsoft researchers proved they aren’t useless. In the study Characterizing and Predicting Email Deferral Behavior, Microsoft Research analyzed 40,000 real emails from employees at large companies to understand why people defer reading emails rather than open them immediately.

Deferring an email doesn’t mean it’s 100% unimportant. Deferred emails can be highly important and often require thorough review and a well-thought-out response.

Deferral may also result from factors unrelated to the message itself, such as the user’s current workload or the device in use. Previous smartphone usage studies show mobile users primarily decide which emails to delete or handle immediately and tend to postpone most emails until they can access a larger device. So, your email might be deferred not because it’s poor, but simply because there’s no laptop handy.

Research Methods

• Qualitative interviews to understand motivations and deferral strategies.

• Large-scale log analysis confirming interview insights and measuring deferral prevalence.

Key Findings

• Deferral is not rejection but a form of prioritization. 56% of users open deferred emails within 48 hours—marketers gain a valuable second engagement window.

• Time of day matters. Most deferred emails occur between 10:00 and 13:00, when workload peaks, with opening delayed to evening or next morning.

• Email type influences deferral. Informational emails are deferred more often than emotional ones.

• Emails with clear calls to action (“Register,” “Download”) are less likely to be deferred.

Overall, users defer emails requiring replies, reading, or clicking links. The decision to defer depends on workload and sender importance, often influenced by mobile device usage and the desire to view content on a larger screen.

Key Takeaways for Marketing

• Launch a second trigger wave—send a follow-up 24–48 hours later if the email remains unopened. No immediate reaction doesn’t mean no interest at all.

• Test timing slots such as Tuesday mornings, Wednesday evenings, and Friday’s office slowdown to find the most effective send times.

• Add a “remind me later” option directly in emails or within the user’s personal account on your website.

• Don’t hesitate to include phrases like “Save this to read later” in your content—this aligns with natural user behavior.