Simple email subject lines are failing to engage consumers

Chart of the Day: Simple vs complex subject lines

Many email marketers keep their subject lines simple and short, but are these causing recipients to fail to read on?

"Not only does this study suggest that complex language leads to greater email engagement, but it also once again proves the value of testing and optimisation."
~ Nikki Gilliland @ Econsultancy

The Automatic Readability index uses the number of characters to gauge the understandability of a piece of text. And that is what is used to create this rather complicated chart.

The chart shows a steady gradient increase in open% and CTO% as the complexity of the subject line increases. The difference may seem diminutive, but remember that this chart is working on a scale of billions of sends. So it can lead to some significant changes.

Before you start making drastic changes, remember to A/B test your subject lines to see if this appeals to your customers.

• Source: Email Engagement vs Subject Line Complexity (Readability Index)
• Sample Size: 675,000 subject lines and the results of 41bn sent emails.
• Recommended Resource: Email Marketing Toolkit