Key Findings from 6.4 Million Sales Emails

Have you ever had a sales person come up and ask, “what do you think about this new prospecting template I came up with Boss?”

The answer is obvious.

“I don’t know. Test it.”

That’s the great thing about so many aspects of sales. Gut instinct is necessary; however, the data can be such a guide for best practices.

Being a data geek myself, I got pretty excited when one of the data scientists here on the Signals team analyzed the results of 6.4 million sales emails. The full report is here.  Below are three observations I found to be interesting.

Observation 1: What’s the best day to send sales emails?  SUNDAY?!?

Should reps start sending all sales emails on Sunday?  Probably not.  But the analysis below suggests your reps should include a weekend “ping” into one of their rotations.

Best Day to Send Emails

This chart plots the number of sales emails sent by day of the week against the open rate of these emails by day of the week.  As you can see, sales email volume is highest in the early half of the week, tapers off on Thursday and Friday, and then plummets over the weekend.  These results suggest that reps come into a week with a bunch of prospecting energy but that energy tapers off by Thursday and Friday and is almost non-existent over the weekend.

On the other hand, the chart shows that, early in the week, the open rates start low, gradually increases, and spikes over the weekend.  What’s going on here?  Well, I imagine that executive decision makers enter a week with a jam packed schedule, struggling to keep up with their inbox.  They finally have a breath to catch up with their email toward the back half of the week  and clean out all the loose ends over the weekend.

Sound familiar?  If so, have your reps try the weekend ping.

Observation 2: Does Time of Day Matter?  Not really.

The chart below shows how the open rate changes as more time elapses from the moment the email was sent.  To be honest, I would have expected the line to level off sooner and at a much lower level.  Instead, the chart shows that 50% of recipients open sales emails within the first 24 hours and over the next 12 days, it flattens out at around 80%.


Best Time of Day to Send EmailsWhen I saw that stat, I thought, “Wow!  More sales emails are being read than I thought.”

The recipient may not open the sales emails right away but in most cases, they are reading them.  Therefore, don’t have reps worry so much about the perfect timing of sending the email.  Focus on the quality of the content to encourage the recipient taking the next step. I personally use Sidekick, a free tool that shows when your prospects have opened or clicked your emails, to better understand when my emails are being opened.


Observation 3: Which Subject Line is Best?  How about NO SUBJECT LINE!

The analysis also looked at how certain words used in the subject line influenced open rates.

Including some words in the subject line yielded a lower open rate, such as:

  •  “Quick” yielded a 17% lower open rate
  •  “FW:” yielded a 17% lower open rate
  •  “Meeting” yielded a 7% lower open rate
  •  “You” yielded a 5% lower open rate

Including some words in the subject line yielded a higher open rate, such as:

  •  “Free” yielded a 10% higher open rate
  •  “Tomorrow” yielded a 10% higher open rate
  •  No subject altogether yielded an 8% higher open rate

I find the results around no subject line to be most interesting.  We spend so much time obsessing over the ideal subject line.  It’s kind of funny that, from a statistical perspective, not including a subject line sometimes performs the best.

So, should we encourage our reps to send emails without a subject line?  I do not know.  It feels disingenuous and sleazy.   However, with certain buyer personas, it may be an effective tactic to at least get the prospect to read your email.  If you do try the tactic, I recommend trying it early in the prospecting sequence so the prospect has not yet associated your email address with a sales person.  Also, I recommend paying close attention to the first few words of the email body, as those words will show up in most email clients in the email summary section.

Well, that was fun.  I love data.  And I love what we can learn.  The full analysis is here.  I would love to hear your interpretations.


Check out Mark Roberge’s new book that launched this week, “The Sales Acceleration Formula”, about building the HubSpot sales team.

Mark Roberge