Is It Time To Re-Think Subject Line Length?

A very interesting study recently released by Alchemy Worx has caused me to re-think what I’ve been teaching about subject line length. In the past, I’ve advised that you keep your email subject lines to no more than 35 characters. The idea behind this “best practice” is that a 35 character subject line is universally acceptable – it will fully display in most email software programs, most web-based email clients and most PDAs without being truncated.

However, Alchemy Worx discovered that while shorter subject line length does indeed lead to higher open rates, what happens after the open might surprise you. In their study of almost 650 email campaigns, Alchemy found that the higher open rates associated with shorter subject lines might also be linked to lower click through rates and click to open rates. Open rates were highest with subject lines of 60 characters or less, but click through rates and click to open rates where highest with subject lines of 70 – 100 characters.

Interestingly, Alchemy found that the worst performing subject lines, both in open rates, click through rates and click to open rates, were those of 60 – 70 characters, or 6 – 10 words.

One presumption mentioned in the study is that today’s email clients have much more sophisticated displays and so there is no longer a need for shorter subject lines. But the take away that I am leaning toward is that the larger subject lines allow the marketer to convey more relevance. While the open rate may be lower, the relevant subject line ensures that the right readers are opening the message – which leads to a higher click to open rate.

How should you apply these findings to your own email marketing program?

First, don’t arbitrarily stuff words into your subject lines just to increase the character count. I don’t think it was the number of words or characters used as much as it was the relevance of the subject line. Use only the words necessary to create a compelling and relevant subject line.

Focus on conveying your value proposition. A subject line that is specific and detailed might require more characters, but it’s sure to be opened by the right readers.

Consider crafting different subject lines for your PDA readers. If you know which readers are accessing your messages from their mobile devices, you might want to send them subject lines of 35 characters or less so they will not be truncated.

Measure what matters. To improve the effectiveness of your email marketing program, it’s important to track your open rates, your click through rates and your click to open rates. But as a small business, it’s even more important to measure your roi and the effect on your bottom line. Don’t leave these important metrics out of your email evaluation.

And finally, test, test, test. Industry surveys and case studies are a great starting point, but every industry, every niche and every audience is unique. You have to test each and every hypothesis with your own mailing list.

You might also be interested in:

• How To Design Your Email Messages For Mobile Devices
• Improve Your Email Open Rates With These Subject Line Tests
• The Secret to Effective Email Subject Lines
• Boring Subject Lines Outpull Hype
• Tips for Better Email Subject Lines

This entry was posted on Friday, April 16th, 2010 at 8:07 pm and is filed under Email Marketing. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.