Mar 04, 2014

New Research Reveals Which Email Subject Lines Perform Best for Marketers

New Research Reveals Which Email Subject Lines Perform Best for Marketers - Retention Science

Six to 10 words yield highest open rates, movie and music themes becoming more prevalent

We have recently completed a new study uncovering the attributes that make up the perfect email subject line - one that generates the highest open rates for marketers. The data was derived from an analysis of more than 260 million delivered emails and 540 campaigns. We found subject lines with six to 10 words perform best, generating a 21 percent open rate, well above industry standard. Those with subject lines containing five or fewer words ranked second with a 16 percent open rate, and those with 11-15 words returned a minimal 14 percent open rate. Despite this, the majority of emails sent (52 percent) had subject lines in the 11-15 word range.

Chart 1 - Subject Line Length

"Subject lines are arguably the most critical component of any email marketing campaign, as they're the first thing people see in their in-box and what they consider when making the decision to open or trash an email," said Jerry Jao. "Our findings show brevity is the key to enticing customers to engage with offers, and ultimately, to click through and convert."

Mobilize and personalize

Our research also revealed that 35 percent of emails are opened on mobile devices. Given that most smart phones only display five or six words of a subject line, being brief and concise is even more critical in the mobile marketing world.

Chart 2 - Name in Subject Line

Taking a personalized approach is also shown to help re-engage and retain customers. Of the email campaigns studied, those with the recipient's first name in the subject line delivered a 2.6 percent increase in open rates compared to those without a name.

Movies and music moving up the marketing charts

Our research also uncovered the use of movie titles and song lyrics in subject lines as an emerging trend. A separate study we conducted analyzed 3.7 million emails and 22 campaigns where movie names and song lyrics were referenced in the subject line, and discovered they perform considerably better. Results showed those with subject lines referencing movies or songs were opened 26 percent of the time, while emails with more traditional subject lines were opened 16 percent of the time.

Chart 3 - Movie or Song in Subject Line

"Email marketing remains one of the most effective and lucrative digital marketing strategies, but there's always room to improve and capitalize on emerging trends," said Jao. "Movie and music references can be targeted to certain customer segments or encapsulate a promotional theme, making them a creative way to hypertarget and capture attention."

Flash sales - a lesson in what not to do

Flash sale sites may be breaking all of the rules in marketing, but are their lengthy subject-lines and frequent mailings proving successful? In our research, nearly 80 percent of flash sale email campaigns had subject lines in excess of 20 words, and they consistently underperformed compared to campaigns with shorter subject lines. Their meager performance can also be attributed to the frequency of which they are sent - flash sale brands tend to email their customers four - eight times a week, whereas the norm for others is two - four times a week.

Research Methodology

We analyzed 267 million emails sent across 543 campaigns in the past six months. Results were normalized to account for varying sample sizes. The campaigns involved retailers involved in specialty goods, apparel, baby products, flash sales, whose and nutritional supplements, among others.

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