Sponsor Insight: We Analyzed Over Half a Billion Internal Emails to Help Communicators Be More Effective: Here’s What We Discovered

Email. It never ends. And now it is more important than ever.

While a zero inbox is a noble pursuit, it takes too much effort. Teams, chat, social intranets and mobile apps all have a place, and actually work better for some collaborative communications, but they have not replaced email for good reason.

To ensure employees read our email and take action, communicators can leverage the insights of data to send more effective and engaging email broadcasts. Here are some interesting tidbits from our analysis to help you send better email.

The email insights you need to know

We analyzed over 650 million internal emails to over 5 million employees globally. We collected this aggregated, anonymous data from over 300 enterprise customers. We also compared pre-COVID-19 email statistics to the current pandemic situation, which I’ll talk about shortly.

Want higher email readership? Here’s what you need to know:

  • What’s this about? The top 20% of communicators send shorter subject lines. Why? Both desktop and mobile previews only display 42 characters of the subject, about 7 words. A short, clear, compelling sentence or curious question works best.
  • You’ve got one minute: After 250 words, about one minute of read time, expect your readership to decline at a rate of 11% every 500 words. The optimal point of readership to message length is at the 1 minute mark, but even shorter performs better.
  • Text or images?: The highest readership rates are on opposite ends of the spectrum, when measured in pixel area, all text or mostly images email work the best, and email that is mostly images (>50% image to text area) performs 27% better than all text.
  • Fewer links for higher click through: Perhaps counterintuitively, the fewer the URLs included within the email, the more likely employees are to click something. When you really want someone to click something, send a shorter email with just one link.
  • Timing matters: While there isn’t one universally best day or time to send email, our analysis does reveal some important timing considerations.  For one, email programs sent on a routine daily or weekly schedule have higher engagement than email sent more randomly.  For another, the communicators within the top 20% engagement rates send a lot more of their email early in the morning, and earlier in the week.

What happened to email during this crisis?

As part of our analysis, we compared email statistics pre-COVID-19 to statistics during this pandemic. Here’s what we found:

Employee email broadcasts doubled, and weekend broadcasts went up 1,100%

During the months of March and April 2020, the number of emails sent through our system to employees nearly doubled from a weekly average of 5.8M in February to 11.3M per week in March and 10M in April. More surprising was the volume of weekend emails, which skyrocketed up 1,121% in March from a normal level of 74,472 per weekend to 909,382.

Accurate distribution lists are more important than ever

This pandemic made evident critical distribution list issues that were a missing part of crisis communication plans. Here are a few of those issues.

  • Inability to quickly target a building or group
    IT or HR requests for targeted list pulls can often take a week or longer, communicators needed those lists immediately. Targeting and relevancy are always important, but never more so in a crisis situation. Often, they resort to more quickly broadcasting to all.
  • Distribution accuracy: Executives, HR and legal/compliance people needed accurate records of message reach – only to recognize their distribution groups were polluted with former employees and non-personal email addresses like conference rooms, and missing new employees, resulting in highly incorrect reach counts. This was never that important, until it was critical.

What’s measured is better managed

While email measurement during this pandemic is often being utilized for a different purpose than improving engagement – Did we reach the impacted employee group(s)? Are we compliant with legal and health notification requirements? It’s clear email is the corporate communications channel which provides the most extensive reach, readership, and engagement. It’s also clear, given the increase in volume, that employees can actually handle more email, despite complaints of email overload.  This strongly suggests email overload is a relevancy, targeting and email length problem. When you don’t waste employees’ time, and provide relevant, targeted messaging, they will welcome your communications. In the end, we found the winning formula to be: Send less content, more often.


Official World Conference Sponsor/PoliteMail – Gain Outlook email intelligence, not overload. To measure and improve internal Outlook email broadcasts to employees, corporate communicators send PoliteMail. PoliteMail Software adds email analytics, responsive HTML design, and list management tools to the enterprise email program you already know how to use, Microsoft Outlook and Exchange. PoliteMail makes it easy to create impressive, highly readable corporate communications, with advanced analytics to enable you to discover the email employees actually read, with key metrics to help you improve results over time.