Open Rate & the Science of Subject Lines

Email subject lines are far more than just random combinations of words; they serve as the digital hinge upon which a message is seen, and directly influence whether an offer is clicked and a user ultimately converted. Subject lines, however, require less artistic or creative muscle than Internet professionals might think.

There's always been a data-driven science to the email subject lines deemed most effective, and there likely always will be, but more often than not, digital marketers rely on their intuition. Over time, the most successful 'Net enterprises have come to learn, through trial and error, what generates the best response with their own audiences and with each new send have even more evidence to prove their assumptions are correct.

The trouble with email is that as consumer tastes and preferences change, so does behavior. Shifting behavior creates unknowns for marketers, but the savviest base their decisions on data. Email marketing service provider MailChimp's recent study provides such a data-driven opportunity to influence how our subject lines are created.

Time Sensitivity: Conveying the importance of an email by expressing the urgency of the digital communication within the subject line is a common practice. MailChimp found that email subject lines that convey time sensitivity, such as those that contain the words "urgent" and/or "important," have open rates that are much higher than normal.

Positive Solicitations: MailChimp's analysis also found that email recipients are much more intrigued by subject lines that contain positive solicitations rather than negative admonitions. Words such as "announcement" and "invitation" have significantly higher open rates than those containing "reminder" and "canceled."

Personalized Communication: One of the most common practices of email marketers is to leverage personalization technology within email campaigns. Buoyed by more sophisticated ecommerce platforms and CRM software solutions, integrating personal elements, such as a name, prove effective when it comes to open rates but not as much as is often expected. However, combining a person's name with some element of time sensitivity can result in much higher response according to the MailChimp research.

Nothing is Free: The use of the word "free" in subject lines is hotly contested and more aligned with poor email practices than good ones. There's certainly a place for its use, but free has been so overused that many marketers shy away from it altogether - and that happens to be to their benefit. Based on MailChimp's study, we know there is only a negligible improvement in open rate when the word free was used in the subject line.

COPY & PASTE: Access some of the most popular symbols for use in your own campaigns.

Symbols for Salience: One trend emerging recently, and which is currently in use by some progressive email marketers, is to use unicode symbols in their subject lines (think hearts, airplanes, etc.). Their use in the past year was embraced as much as it was questioned. There's clearly a fine line walked by marketers using unicode symbols as they can turn off a prospective email opener quickly.

Mailchimp's study will likely debunk numerous long-held myths about subject lines, but for many email marketers it will raise even more questions. If you're looking for a more straightforward approach for how to best craft email subject lines, consider the suggestion from AWeber that clarity trumps creativity. In fact, according to its own research, clear subject lines outperformed "cutesy" subject lines no matter what metric they looked at - comments, tweets, likes, traffic, subscriptions, etc.

"A lot of people assume that creative subject lines will get the most clicks, but that's not necessarily the case," said AWeber CMO Erik Harbison. "People don't want to have to guess what's inside an email. They want to be told why they need to read something so they can move on to the next thing. So as a general rule when it comes to the subject lines, specific, clear and concise is the better way to go."

Harbison suggests that marketers always test email lines because every subscriber base is unique. "If you're a company that's known for being quirky and creative, your audience might be more likely to open an email with a creative subject line," said Harbison. "The same might be true of a specific group of subscribers that's really engaged with your emails. They may respond differently to creative subject lines than new subscribers. So, the real answer to crafting the best subject lines is to get to know your audience and the segments of your audience through testing."

When you stop and think about how many emails go through a typical inbox on any given day, it becomes obvious how being clear and direct will improve the performance of your campaigns.