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The One-Thing Rule for Email

If there is one principle regarding writing an email that you should follow, it is the One-Thing Rule.  Before I go any further, I admit that I sometimes violate this rule.  Many wonderful, effective, and valuable emails break the rule.  But the routine and intentional application of the One-Thing Rule improves the rate at which your emails work.  This rate is the percentage of your emails that achieve the desired result.  You want information exchanged with the recipient(s) and action by them in response to your request.

The One-Thing Rule Explained

So what is it?  What is the rule?  Simply this:  When writing an email, discuss only one topic.  The corollary to the rule is that the subject line must accurately reflect the same topic.

The primary reason for this is obvious:  If you start with the perspective that email is all about the reader, then the One-Thing Rule makes it easier for the reader to understand the message, evaluate their options, and take clear action.  If two unrelated topics are in the email body, then the reader has a choice – which one to consider first? 

After making that choice, one of two things will happen.  Either they will return to your original email to pick up where they left off to consider and process the second topic, or they will move on to something new.  That new thing could be another email that has entered their inbox.  Mentally they mistakenly think that they have completed dealing with yours.  Or, if your first topic caused them to move away from the email (to a file, webpage, reference, or another email in their archive), they might have found something more exciting and distracting.

Regardless of how their attention span was broken, the second topic has a different attractiveness to them than the first topic.  Remember, the first topic arrived in a new, unread email in their inbox.  The second was a tag-along.

And It Gets Worse

If you violate the One-Thing Rule in the body of the email, the problem for you is exacerbated by the dilemma of what to write in the subject line.  The subject line should reflect the message, but how do you do that when there are multiple messages?  Do you write multiple subject phrases and jam them together in one line?  This is not practical and leads to cryptic subject lines such as “Questions from me,” “Stuff to think about,” or “Catching up on several things.”  None of these are very helpful.

The subject line is helpful to help you spot when you are violating the One-Thing Rule.  If you spot the word “and,” if you feel the need to add a comma or semi-colon, or if you write a subject line that is vague and non-specific, you probably are breaking the One-Thing Rule.  Do yourself a favor.  Break the message into two (or more) separate emails.

What the One-Thing Rule Doesn’t Mean

The One-Thing Rule does not mean that the message, although covering one topic, can’t have multiple questions or multiple steps.  The key is whether they are related or not.  A shopping list can include multiple “things,” but asking the recipient their thoughts about a planned trip to a state park next weekend is a separate topic from the grocery list and you shouldn’t include in the same message.

Or perhaps a work-related example: Asking the recipient to send you a copy of the latest weekly status briefing is a single topic.  The email shouldn’t also have a second discussion about the contractual implications of the recent revision to the policy guidance.  Separate these two – and the first one could be a one-liner email request that the recipient can reply to (with an attachment), then delete and complete.  The second email may start a back-and-forth discussion, and eventually involve others added to the conversation.  Later, no one has to waste their time and energy reading through the email trail and seeing a second discussion about the weekly status briefing. 

Benefits of the One-Thing Rule

Pay attention to the rule while writing your emails.  You will find fewer unanswered questions, missing replies, and abrupt changes to the conversation in email.  Your emails will be more concise, clear, and actionable.  The One-Thing Rule will make email what it is supposed to be – a tool to aid productivity and enhance collaboration within your team.  For more ideas about managing emails and inboxes, see my review of The Email Warrior.

If you want to dive deeper into email writing, consider taking my Writing Compelling Emails course. In this 90-minute online training, you will learn how to create emails that get your point across, get noticed, and result in the desired action.

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