Epsilon recently published a study reaffirming the near universal email marketing adage that shorter subject lines perform better. However, their research indicated that while there is a positive correlation between subject line length (SLL) and open and click rates it may be weaker than is widely believed. Epsilon compiled data from 5 of its retail clients over the period of June 2007 and June 2008. The data was measured against a control group to validate the findings between subject line length and response rates. They found that shorter subject lines outperformed longer ones but that the results were also dependent on the company or brand.
The study suggests that the positioning of words in the subject line, what they call ‘pole positioning’, may be just as important a factor as SLL in creating a successful email campaign. Their research seems to affirm the hypothesis of pole positioning greatly impacting open and click rates.
The study provides two subject line structures and examples to illustrate the point:
time>brand>benefi t>category structure
or
benefit>category>brand>time structure
Subject line 1:
“This weekend only at your local Acme Store, special savings on Ladies Apparel!”
Subject line 2:
“Special savings on Ladies Apparel at your local Acme Store this weekend only!”
Both subject lines are the same length but how your reader interprets them will determine which will perform better. Knowing how your specific target audience responds to different messages will help you achieve better email marketing results.
The example below was given to show how word order or choice can trump SLL as the determining factor for email success.
Subject line 1:
“Last chance to order for Valentines Day
is this Wednesday, Order Now”
Subject line 2:
“Only 48 hours to order for guaranteed
Valentines Day delivery”
Although subject line 2 is shorter, subject line 1 delivered a 23% lift in sales. This suggests that SLL isn’t always the determining factor and that ‘pole positioning’ can significantly impact the outcome of an email campaign.
MailChimp, an email service provider (ESP), cited one of its clients, GoodNites, as an exception to the shorter subject line is better rule. GoodNites averaged 94 characters for its SLL yet their research revealed a correlation with SLL to a unique open and rate and total click-through rate of .47 and .53 respectively. In 14 of 22 (64%) A/B and A/B/C subject line tests, the longer subject line performed better.
This research just goes to show that there are exceptions to every rule. The important takeaway is to review your own email marketing successes and failures. See what works and what doesn’t work for you and apply what you’ve learned to create more successful email campaigns. Test, Test, Test! That is the key.
Download the full Epsilon report on ‘The Long and Short of It: Perfecting the Art of Email Subject Line’.
