Choose Them Wisely: How Words Affect Email Open Rates

Are your subject lines helping or hindering your email open rates? To find out, we looked at two pieces of research that drill down into the details of what makes an email subject line irresistible to readers.

The first is a whitepaper from email data solutions provider ReturnPath that analyzes the performance of common keywords in email subject lines. The report found that words that subject lines that express "Urgency" performed the best, followed by "Benefit" and "Command" (those that tell the reader what to do).

Surprisingly--and perhaps happily for those of us sick of seeing them--"Clickbait" type subjects (e.g. 3 Things Realtors Should Never Do. #2 Will Shock You!) performed poorly. This doesn't mean that they're ineffective on other channels, like social media or blogs, but it does indicate that you should think twice before crafting your email subject lines in that style.

Below is a brief sampling of how different keywords performed. The numbers indicate how that word impacted the open rates when compared to other subjects lines from the same brand.

Benefit Keywords

Superlatives seem to perform well in subject lines--but you have to be careful about which you choose. While email recipients love things that are the "fastest," they're much less enthusiastic about things that are "quickest."

• Fastest: +5.3%
• Prettiest: +2.87%
• Cheapest: -2.94%
• Quickest: -2.01%