(Update: It turns out there are also separate reports showing the best closing phrases and the best day of the week to send emails if you want a response.)

How many emails do you send a day? Depending on your job, it could be dozens, thousands, or more. If you're into email marketing it could be in the hundreds of thousands or millions. 

What if we were to tell you that simply changing the initial word you use in your emails could significantly improve the odds that people will be prompted to reply?

The folks at Boomerang, in a report reprinted on Quartz, combed through more than 300,000 publicly available emails--most of which had been included in threads on various online forums over the years--pulled out the most commonly used opening words, and studied the response rates.

They found five words that started at least 1,000 of the messages in the trove:

  • hey
  • hello
  • hi
  • greetings
  • dear

Across all emails, it turns out that simply using the informal, three letter opening "hey," prompted more responses: Exactly 64 percent of emails that opened with that word received replies. 

"Hello" and "hi" didn't fare too badly either: they had 63.6 percent and 62.7 percent reply rates respectively.

From there, however, everything dropped off. 

"Greetings" resulted in a 57.2 percent response rate, and the traditional opening, "Dear," led to a 56.5 percent response rate. 

Those openings still beat the average of all emails across the entire trove, however, which had a 47.5 percent combined response rate.

So, does that mean you should open every email you send with "hey?" 

Probably not; it might be too informal for some cases. And it might get repetitive to the point of cliche.

Plus, there are other really good practices you might include in your emails to increase your response rate, such as using the recipient's name in the greeting (at least sometimes), and writing in an emotionally intelligent manner.

My colleague Justin Bariso did a great job recently of explaining this, in an examination of how Steve Jobs wrote great emails

But all things being equal, if you're not already opening the occasional email with the greeting "Hey," you might give it a try--and pepper in some "hi" and "hello" openings, as well.