Effective Subject Lines
Subject lines are required for emails and memos, and they are often included in letters, too.
According to the style guide at Canda’s Public Works and Government Services,
Subject lines are particularly important because of how audiences use them. Often, an audience member will decide to read, or not read, a document based on its subject line alone. If the subject doesn’t appeal to the reader, she or he may assume the content of the message doesn’t apply to them (or isn’t important to them).
Subject Lines Should Reflect Purpose, Main Idea, and/or Content
In general, subject lines for informative (neutral) and positive messages should be specific and informative. They should communicate the purpose of the document, summarize its main point/s, and/or describe its content. Be as direct and specific as possible, and don’t limit yourself to just one or two words. Remember, it’s not a title (a name); it’s a subject (a topic, matter, or what it’s about). Write enough to communicate your purpose, topic, or main point of the message.
| INSTEAD OF | REVISE TO |
| Ella Fitzgerald | Interview Questions for Job Candidate Ella Fitzgerald |
| Deadline Approaching | April 15 Deadline for FAU Graduate School Applications |
| Dept. Bylaws | Request for feedback on Dept. Bylaws revision draft |
Note: You have some choices when it comes to subject line capitalization. For email subject lines, you may use initial style capitalization (title case) or sentence style capitalization (never write email subjects in all caps). For subject lines in letters and memos, you may use initial/title case, sentence style, or all caps.
See here for more information about email subject capitalization.
Balance Clarity & Specificity with Conciseness
Inasmuch as subject lines should be clear and specific, when it comes to emails, you also need to balance clarity with conciseness. Be aware of the various contexts in which your audience may read your correspondence. When it comes to email, that means your audience may read your message on a desktop email client or on a mobile device with an email app. According to Business Insider, approximately 50% of emails are read on mobile devices.
Most mobile and desktop email applications cut off email subject lines after a predetermined number of characters (characters = individual letters and spaces). While the length of what’s shown varies by device and application, averages and estimates suggest desktop clients show "about 60 characters of an email’s subject line, while a mobile phone shows just 25 to 30 characters."
For that reason, be sure to "front load" email subject lines with the most important information first. Also, feel free to omit articles (a, an, the) and use ampersands (&).
Subject Lines Should Be Appropriate for Purpose & Organization
Additionally, a subject line should be appropriate for the document’s pattern of organization, which is often determined by its general purpose. While we will cover organizational patterns for negative or bad news messages in later course material, for now, keep in mind that the information on subject lines here applies to routine positive and neutral messages and/or routine request for information. The rules for negative messages are a little bit different (again, there will be more on this later).
Considerations for Digital Communications
If you are going into marketing or simply interested in the additional elements and opportunities provided by digital technologies, encourage you to do your own reading about email meta tags, snippets, preview text, and preheaders. All of these are useful opportunities that increase the chances your audience will read your email, particularly in the case of mass emails, advertising, and networking messages. Since they aren’t convenient for direct person-to-person email communications, were not going to cover them here.