Test Details:

Western Governors University (WGU) an American online educational institution, conducted this smart subject line test in-house for Valentines Day.

Background:

Wanting to know what would get readers opening the email, the testing team drafted four email subject lines — each with a slightly different twist.

The first two subject lines were conversational in nature. They stated:

• “Give Your Career a Little Love”
• “Show Your Career a Little Love”

These “feel good” subject lines were formatted in Title Case. They only difference between them was one started with the verb “give.” The other started with the verb “show.”

The next two subject lines took a more transactional, or business-like approach. They stated:

• “Your online match is here”
• “Your online match is here:”

These more matter-of-fact subject lines were formatted in Sentence case. The only difference between them was that one version ended with a colon.

Pondering the power of punctuation, the team wondered if adding a colon would impact results.

Hypothesis:

The team wasn’t sure which variation would perform best — and, therefore, decided to test. However, they thought the transactional subject line, with a colon at the end, would imply the most benefit, enticing more readers to open the email.

Test Set-Up:

To test which subject line worked best, an email marketing campaign was set-up and run on Marketo’s marketing automation platform.

The email offered prospective students — who had not yet enrolled at the university — an application fee waiver. The waiver was worth $65.

In total, 104,797 prospective students received an enticing email, with one of the four subject lines.

Traffic was initially split evenly across the four variations. However, once statistical significance was achieved, all traffic was directed to the winning version.

Email sends, open rates, click to open rates, and unsubscribes were tracked across all versions.

The Real-Life Result:

Winner: Version B – the subject line stating, “Your online match is here:” matched up as the strong winner.

It took a “transactional” approach, suggesting, if readers opened the email, they’d get something tangible in return: their online match.

The losing subject line — which stated “Give Your Career a Little Love” — came across as more “conversational” in nature. Although it may have been viewed as friendlier, it offered less immediate benefit.

The winning text far outperformed all variants by all measures.

Looking at percentage of opens, the winning version, “Your online match is here:” achieved a 29.57% increase, compared to the biggest loser, “Give Your Career a Little Love”.

A similar trend occurred for the click to open rate percentage. The winner, “Your online match is here:”, saw a 8.83% lift in opens, compared to the losing variant “Give Your Career a Little Love”.

It’s important to note that looking at the differences in percentage form helps smooth out any discrepancies in the amount of traffic directed to the winning variant. However, traffic was equally allocated to all four version until a clear winner emerged.

Not surprisingly, because the most traffic was sent the winning message, the unsubscribe rate was also highest for this winning variant. However, the number of users converting on the offer far outweighed those who unsubscribed.

A full results breakdown can be seen here:

Results achieved 99% confidence.

Analysis:

Let’s get down to business!

The winning subject line — “Your online match is here:” — took a transactional, or business-like approach. It told readers the immediate benefit of what they’d get. Right here, right now. The copy implied readers could immediately obtain something they were seeking: their “online match.”

The benefit was not as obvious with the subject lines containing more conversational copy. With these subject lines, readers were told to give, or show, their “career a little love.” But, there was no explanation of how to do so, or what would happen if this objective were met.

However, wording was probably not the only factor swaying users. Subtle subject line cues were likely just as important.

The formatting of the text – in title versus sentence case — likely impacted reader flow and cadence. Because the winning version was formatted in sentence case, the words flowed more smoothly.

And, the version with the colon likely outperformed all others because it properly punctuated the message.

The colon implied a list of benefits would follow in the email. But, to get to those benefits, readers needed to first pause and take note. Then, with full attention, engaged viewers could take advantage of the savings discount offered.

No other message used the colon to direct the reader this way.

Punctuation can be powerful. It acts like a traffic signal. It tells the reader when to stop. When to go. And, how quickly to proceed. Readers need these signals to fully grasp the message.

Proper punctuation isn’t the only sign of a successful subject line, however.

According Mike Madden, Head of Demand Generation at Marketo, there are seven strategies for crafting smart subject lines. They are:

1. Know numbers are number #1. Use numbers to quantify benefits
   • For example, write “3 secrets to killer emails” instead of “The secrets to killer emails”
2. Capture the reader by frontloading, or putting specific information upfront
   • For example, the subject line “Seven hacks to boost your email open rate” will likely outperform “boost your email open rate with these 7 hacks”
3. Use questions. Why? Because they convert!
   • For example, “Did you miss this?” will probably evoke more curiosity – and clicks — than “You missed this”
4. Use the pronouns “you and your” to make your message feel more relevant
   • For example, “Why you need to add this technique to your daily routine” will probably outperform “Look what happened when I added this technique to my daily routine”
5. Create creative subject lines. Remember rhyming and alliteration almost always win. People love to read things that read well
   • For example, craft copy like “Social media marketing dance, brands, and fans” or “An unusual arsenal of tools to topple a tech tyrant”
6. Be honest and truthful. No matter how compelling your subject line, make it sincere. Just like a link is a promise, so is your subject line
   • For example, say, don’t say “This offer ends tomorrow” – if it’s not true. Instead, say “Click to get your enrolment discount now”
7. Think of an email subject line as your primary Call To Action (CTA). To be effective, it needs to be clear, directive, and tell readers exactly what they’ll get from clicking
   • For example, say, “click here to watch this informational video.” This information tells readers what they need to do and what they’ll get from taking action. Don’t say, “Check out this amazing work.” That doesn’t say anything.

And, most importantly, remember: test, test, test! While these guidelines will help you create killer email subject lines, it’s always important to test what works on your site, with your specific audience.

Ultimate Takeaway & Immediate Application:

The tone, style, and text of your email subject line can dramatically affect conversions. Even something as simple as the Case of Your Letters, adding a colon, or choosing the right verb to start your sentence can make a big difference. So, test your subject lines with your specific audience and examine not just wording, but also grammar, style, and sentence structure.

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