Business owners and sales professionals lament the poor response rates of their emails. Your subject line largely determines whether your email is opened. If the subject line doesn't grab them, you can forget about your email being read.

You might think it's obvious that if you send an email, the reader should open it and act on its contents.

Not so fast.

The average businessperson receives over 121 emails a day. Some people receive several hundred emails daily. Dealing with email takes up to 11 hours a week for most workers -- and much longer for others.

Given the cascade of communication your reader is receiving, why should she respond to yours?

If your email is immediately relevant to an issue that she considers important, she will probably respond promptly.

However, even the most well-meaning reader is barraged by email all day long. The email tsunami renders readers numb about how to respond. So here's the secret: Don't wait for your reader to figure out what you want him to do. That might never happen.

Here are three elements to include in your subject line to trigger a response from reluctant readers.

1. Tell the reader what to do.

If you want your reader to respond, tell him what action to take. Based on my experience teaching email effectiveness for decades, here's my suggestion: Tell the reader what to do. By writing Please Respond or Action Required at the beginning of a subject line, clients tell me that their response rates soar. In your subject line, write phrases like:

  • Please Respond
  • Response Required
  • Immediate Action Required
  • Please Approve
  • Please Confirm

For example, after a successful initial training, a major seafood wholesaler told me that they wanted to proceed with a series of writing training programs for their sales team. I wrote to the sales manager, then left a message on his cellphone, and then waited politely for a few days. No reply.

Finally, I sent another email with the subject line Please Respond: Closing Your File. In the email, I wrote that if he was interested in pursuing the engagement, he should write back; if I didn't hear from him, I would close his file. He responded the same day to say that he'd been very busy but was still interested. I could have written the subject line Following Up or Checking In and I'd still be waiting for a reply.

2. Tell the reader when you need it.  

People respond to deadlines. When everything seems urgent, how do people decide whom to respond to first? Often, the message with a credible deadline moves to the top of the pile.

Think of your own experience. If you receive a subject line that says Documents Needed, will you rush to send the required files? But if the subject line says Documents Needed by Tuesday EOB, you are more likely to respond by Tuesday.

So your subject line might say:

  • Friday Approval Needed: Purchase of New Scanner
  • Respond by 5:00: Audit Report Review
  • Please Confirm Now: Lunch Today at 1:00?

3. Tell the reader why it matters to them.

Adding a "hot button" spin to the subject line will generate more responses.  How will your reader benefit by opening your email? What will it cost him to ignore you? Don't be manipulative or salesy when you touch hot buttons. For example, you wouldn't write Act Now While Supplies Last! because that sounds like spam. But you could write Send Docs Today to Avoid Late Fee.

If you met a person and exchanged email addresses, tell them briefly in the subject line to remind them that you are a person they want to know.

Turbocharging the subject line

Imagine that you have a customer who has orally agreed to a deal. You have sent them the contract. Days creep by and they have not signed. If they don't sign by Tuesday, you will no longer be able to honor the project deadlines in the contract. What do you do? Compare these subject lines.

  • Following Up on Contract
  • Checking In on Contract

Yawn. You can keep waiting.

When that doesn't work, you could try:

  • Signed Contract Needed by Tuesday EOB

That might work. If you want to turn on the turbo, you would write:

  • Action Required: Signed Contract Needed by Tues EOB to Avoid Project Delay
  • Avoid Project Delay: Sign and Return Contract by Tues EOB

Just like you, your readers are rapidly scanning the emails in their inbox, making instantaneous decisions about which will receive their precious attention. To gain your readers' notice, your email needs to jump out from the lineup.  

By asking your readers to act, you trigger the deeply ingrained impulse to do what we're told. By adding a deadline, you increase urgency. And by showing them what's in it for them, you add motivation.

Try this approach and watch the responses roll in.