Sizing up E-Mail Subject Line Length

Guess which e-mail subject line performed better?



By most accounts, it should have been subject line 2 -- it's shorter and follows a best practice of including a numeral. That wasn't the case, however.

The first subject line is credited with providing a 23 percent lift in sales for a florist. Why? Thane Stallings, an Epsilon senior analytic consultant and the author of the white paper, "Rethinking the Relationship between Subject Line Length and Email Performance,," suggested it may be due to the absolute deadline "last chance" versus "48 hours." Plus, the first subject line referred to the holiday earlier in the subject line.

His advice?
--Front load subject lines with the most important information.
--Keep the subject line as short as possible to convey the message.
--Use longer subject lines only when there is a compelling reason to do so.
--When in doubt, test.