I recently had an interesting conversation with someone about Subject line testing…

“Where do I start?” he asked.


I thought I would share the why? how? and what? that we discussed..



You have just a few seconds to generate interest in your email  so a compelling subject line can be key in grabbing readers attention as they scan their inbox.  Testing a couple of ideas to maximise impact is time well spent!


  • Try doing split tests across a series of emails.
  • Test a couple of subject lines with 10-20% of audience day the before the final send.
  • Send the best performing subject line to the bulk of the list


  • Monitor trends and identify what behaviour recipients demonstrate
  • Are their variances by sector?
  • Look beyond opens to clicks and response rates to understand motivations


  • Branding vs. no branding, placement at the beginning vs. end of subject line
  • Informative (statements) vs. engaging
  • Asking questions, clear calls to action
  • Length: Long (>70 chars) vs. Short (<50)
  • One vs. multiple value propositions/interest triggers
  • Personalised vs. non-personalised
  • Sentence case vs. Title Case vs. Capitalisation
  • Emotive copy vs. product-price centric
  • Search engine words vs. website search terms

Getting subject lines ideas

Visit  your own Inbox for ideas. Which subject lines spark your interest and get you opening? Which messages do you delete straight away? Which ones do not delete or file, but never quite get around to reading?

Dare to be different. Often companies stick with  generic subject lines, such as “May Newsletter” to try and appeal to as many people as possible. It helps to remember that generally only 25 to 50 % of recipients are opening your emails to begin with and these are those most likely to do so anyway so something different may reach those apathetic subscribers.

And for something really different look at this from Firebrand!

Good luck and let me know how you get on!