After analyzing more than 260 million emails across 540 retail email marketing campaigns, marketing analytics firm Retention Science found email subject lines kept at 6 to 10 words resulted in a 21 percent open rate.
According to the study findings, while 6 to 10 word subject lines delivered the highest open rate, email subject lines with 5 or fewer words generated a 16 percent open rate.
Retention Science claimed 52 percent of the emails the company evaluated had subject lines with eleven to fifteen words, dropping open rates to 14 percent.
Email Open Rate by Number of Words in Subject Line
While some studies have reported email marketing mobile open rates as high as 65 percent, Retention Science said 35 percent of the emails in its study were opened on a mobile device, reinforcing the importance of keeping subject lines short:
Given that most smartphones only display five or six words of a subject line, being brief and concise is even more critical in the mobile marketing world.
To help increase open rates, Retention Science recommends using a person’s name in the subject line, or a movie title or song lyric.
The study discovered email subject lines personalized with a recipient’s first name lifted open rates by 2.6 percent.
Email Open Rates with Recipient’s First Name in Subject Line
Retention Science noted the emerging trend of using movie titles and song lyrics in subject lines has also helped email marketers increase open rates.
“Movie and music references can be targeted to certain customer segments or encapsulate a promotional theme, making them a creative way to hyper-target and capture attention,” says Retention Science CEO Jerry Jao.
Citing a separate study, the analytics firm revealed subject lines with movie titles and song lyrics had a 26 percent open rate, compared to emails with “more traditional subject lines” that resulted in a 16 percent open rate.
Email Open Rates with Movie Titles or Song Lyrics in Subject Line
Retention Science is scheduled to publish its finding on March 4.