3 Data-Driven Examples of Good Email Subject Lines

good email subject lines

There aren’t many resources to instantly assess the results of your marketing campaigns quite like email. You ship out an email, and after a few hours, you can glean insights on what’s working and what’s not. We’ve talked about how to create performance-driven messages in the past (Reminder: by incorporating emotion), but if you’re like me and want to see how it’s done, we’re going to show you how to create good email subject lines. We’ll go over three experiments Persado worked on in 2018 and give you the winning message we’ve constructed, and the analysis behind it, so you can see higher results in your campaigns. 

First, we’ll share a series of subject lines so you’ll know what to look for when starting out. 

Best Practices for Emotionally Driven Subject Lines

Example #1: Your extra 10-15% off is waiting, but only until midnight! Family & Friends ENDS SOON

There were multiple factors at play when we ran this experiment in January for a retailer: 
1. We were testing to see whether "Ends Soon" is the most effective and engaging language.
2. We also wanted to look at the impact "Ends Soon" and other emotional concepts at the beginning vs. the end of the message.

The client’s message begins with the offer (“Your extra 10-15% off,” which is descriptive language). However, Persado research has shown emotion contributes to 56% of email click-throughs. That’s higher than symbols, formatting, positioning of language and even describing what the actual product is. Because of this, it was worth testing to see whether it would be more effective to lead with emotional language. What we found: 

1. Taking out “ends soon” consistently showed the best results. Subject lines without the phrase had 28% average lift in clicks. 
2. Placing emotional language at the beginning of the subject line also had a significant impact on performance. This contributed to 12% of the overall performance. 

Ready to see the winning subject line and its results? 

Persado: Family & Friends CONFIRMED: Your extra 10-15% off is waiting, but only until midnight! 
(Click lift: 34%)

Why did it perform well? 
For starters, the subject line incorporated some form of introductory statement, a tone-setting, attention-grabbing word or phrase that prefaces or complements what you are selling. Also of note, putting a positive spin on this email netted positive results. And perhaps most importantly, anytime you can incorporate emotion, go for it, especially in this case. 

Aim to refer to the above as you create your own promotional subject lines, and you’ll find that they will perform better. 

How to Turn Your Subject Lines from Better to Best

Example #2: Be the first to grab this deal!

People get caught up in the words, but how do those words make you feel? This original subject line is a great example because it initially looks good — who wouldn’t want to be the first in line for something cool? But the subject line could be better, as we saw in a test Persado did for a retail and eCommerce company in April.  The main emotion behind “Be the first to grab this deal” is Encouragement. According to our findings, that emotion doesn’t perform particularly well. With one subtle change, the subject line went from evoking Encouragement to Exclusivity. And it became a winner! 

Persado: You're first in line for this deal! 
(Click lift: 22%)

How to Write Your Subject Lines Using Anxiety Language

Though it’s a negative emotion, Anxiety has been rising to the top of Persado’s emotional rankings in recent years. In 2017, Anxiety was the top performing emotion for retail and eCommerce email subject lines, yet it can get tricky to convey. Here’s an example from May 2018 on how you can write a message that induces anxiety instead of the less desirable negative superlatives:

Example #3: Hours left! Don't let this offer expire

This subject line uses classic Urgency and Guilt language to persuade a visitor to click on the email for a fashion retailer. When sent out to 31,500 people, it received an open rate of 8.98% and a click rate of 0.823%. In that same experiment, for the same brand and audience, we tested: 

Persado: ✳ This offer requires your immediate attention
(Click lift: 53.96%)

Do you notice a difference in the way both of these messages make you feel? No, neither elicits feelings of warmth and fuzziness. The first message is playing the FOMO card, while the other puts you on high alert. It’s small, but it has shown that it can make a big difference. This subject line received a click-through rate of 1.267% and an open rate of 10.102%, uplifts of 12.53% and 53.96% respectively.

Closing Statement

The beauty in email is that you get instant results on the messages you push out for your brand. This allows you to continuously test what language works best for your brand and what to avoid. All of these results are sent out with conversions in mind. Although we are talking about subject lines here, these are items to keep in mind of when it comes to writing copy as a whole in any of your marketing channels.