Our friends at MailChimp, the online email and newsletter service, have done some pretty nifty research on how individual words used in subject lines affect open rates. The popularity of their service has provided them with a pretty large sample size to work from—something like 24 billion emails! From that massive group they were able to look at approximately 22,000 distinct words and see if any relationships existed between the words used and open rates. According to MailChimp, the numbers are based on “standard deviations from the mean open rate for a user/list.” Some of their findings may surprise you…
- Personalization. Using personalized names in the subject line definitely had a positive effect on open rates, but this effect was much more dramatic when both first and last names were used. When employing both first and last names, the email was 33% more likely to be opened, as opposed to 17% for last name only, and 9% for first name only.
- Free vs Freebie. Which word do you think had the better open rate? “Freebie” was the winner with a 26% increase as opposed to “Free” which came in at 2%. An interesting aside: not all industries were positively effected by the “Free” approach. The retail, business/finance, medical, real estate, and travel sectors were adversely affected by the use of the word “free” in the subject line. The recruitment/staffing and restaurant sectors showed the most positive impact from “Free” (+45% & +11%, respectively).
- Time sensitivity. The words “urgent” (79%), “breaking” (68%), “important” (55%), and “alert” (31%) all proved extremely effective at increasing potential open rates.
- “Thank You” works. Using the word pair “Thank You” in subject lines increased the open rate by 57%, as opposed to “Sign Up” or “Last Chance” which actually had a negative effect on open rates.
- Capitalization. I’ve never been a big fan of using ALL CAPS IN SUBJECT LINES, but research shows a 7% boost in open rates when all caps were employed. Contrast that with -1% when at least one word is capitalized.
It all goes to show how important a single word can be in your subject lines, and how a little tweak can have a dramatic impact on the effectiveness of your email marketing campaigns. You can explore the results of MailChimp’s research in greater detail by viewing the blog article in its entirety.