Home How to A/B Test Your Email Subject Lines and Drive Results

How to A/B Test Your Email Subject Lines and Drive Results

73% of marketers agree that email marketing is the best channel for a brand that wants to increase ROI. Moreover, brands that invest in email marketing get $40 for every $1 invested. Those are just a few stats that lay bare the impressive results of email marketing.

Test Your Email Subject Lines and Drive Results

But to enjoy these returns, brands need to do their best to ensure that their emails are eye-catching, opened, read, and make users take action. This requires a little tweak in your emails and testing one element over another — is the way to test.

The components in your emails to test for better ROI include subject lines, personalization, images, email length, email layout, call-to-action (CTA), and your offers.

Here’s how to A/B test email subject lines or what variables in the subject line to test. Plus, share the benefits of testing subject lines and what to consider before you do an A/B test on your email subject lines and drive results.

What is email subject line A/B testing?

Email subject line A/B testing or split testing your email subject line involves creating and comparing two or more versions of your subject line and separating one that performs better or sparks your audience interest.

After identifying subject lines that serve better, you update your email marketing strategy to improve open rates and increase conversion.

Advantages of A/B testing email subject lines

The number one goal of split testing subject lines is to remove assumptions and guesswork in your email marketing campaigns and get more information to handle future email campaigns better.

Thus, it would be best if you were persistent and committed to challenging your own perception. Split testing email subject lines are meant to:

  • Increase your open rates: subject lines play an important role in whether an email will be opened or not, as they are the first thing that people see in the inbox. Hence, testing your subject line is essential when you have a low open rate. Your open rate is a comparison of the number of unique opens to the number of emails delivered. The better your subject line, the more people will open your email and read through it.
  • Set up campaign timing: do you know that subject lines can tell the best time to send your emails? Yes, you can analyze the results from your test and find which time of the day you receive the most open rates. You can then set up campaign timings to understand your users’ habits to improve engagements, leads, and sales.
  • Find data to back up your email marketing campaigns: data can help you know more about your audience and understand what subject line or campaigns work better to increase the value of the dollar invested.

You can also translate the data into other channels like social media or websites.

For example, if personalization in your subject lines works well with the audience, you can translate that to your landing pages or blog titles, or social media posts to capture visitors’ attention and convert more customers.

8 Email Subject Line Variables You Should Test to Drive Results

To design effective subject lines that generate more open rates, you need to identify what variable to test.

Here, your creativity and research skills play an important role, as well as the resources at your disposal. You don’t want to overstretch yourself or constrain your resources such that your campaigns produce data that is not meaningful.

1. Length

For subject lines, there is a consensus that shorter subject lines work best. While this may be true, it does not have to be the case as each niche or industry has different audiences with different preferences.

Too short subject lines may leave out important information that may not entice the audience to open your email, and too long subject lines may not make some content not visible on mobile.

We also have a case of the number of characters allowed by different email clients and devices, usually between 45 and 70 characters. Finding out if your users feel intrigued or irritated by longer or shorter subject lines will help you pinpoint the precise subject line to use.

2. Creating a sense of urgency

This is a little tricky and may make you appear as salesy. However, when used correctly, it can skyrocket your open rates. To effectively implement urgent languages, combine urgent words like “Now” with active words like “Act.”

The above screenshots show two email subject lines that appear to create some sense of urgency and scarcity by telling users what they stand to gain or lose.

Use urgent language to promote what is inside the email, offer something scarce, set a deadline, solve a complicated problem, or send a warning. You can implement the scarcity principle on one test variant and watch how users react for fear of missing out.

3. Adding emojis

Emojis can also be used to determine the effectiveness of your subject lines.

Research shows that adding emojis affect both open rates and also your subscribe/unsubscribe rates. With emojis, keep your subject line consistent and add one or two emojis to your test variant. Here’s an example from Open Spaces.

Second, keep your emojis relevant and consider your audience, sex, and whether you are a B2B or B2C before you use an emoji.

4. Capitalized words and sentence cases

A highly debated matter with email subject lines regards capitalization of every word, the first words, or proper nouns.

While capitalizing all the words looks shady and unprofessional, some brands have gotten away with it with impressive results. From the screenshot below, you can see how the two subject lines written in the title case would easily capture the attention of any email subscriber.

Sometimes, an all capitalized subject line may trigger sperm filters. The proper way is to use sentence cases or only capitalize the first letter. You can also capitalize the subject line when sending a warning.

5. Single-word subject lines

Single-word subject lines are about capturing your audience’s attention with one word. Warby Parker’s single-word subject line “Welcome” creates suspense and curiosity, nudging a user to find out what it is all about.

Single-word works great when they can inspire emotions or create curiosity. It is also ideal when most of your readers read their emails from mobile phones or have a wordy title that may not be clearly visible on small screens.

6. Statement vs. question

Vague subject lines have the power to pull people to open your emails. But they have to be interesting enough to spur action or users will start to ignore you. Add some emotional element or surprise to exceed the user’s expectations while avoiding false promises and overuse.

On the other hand, statement subject lines are important when a brand wants to be clear in its message or display brand personality and capture user attention. Here are a few vague and statement subject lines you can try on your audience:

  • Hey
  • I hacked your app
  • Read this
  • 3-steps to build a better mailing list
  • New Jobs for you
  • Email automation tricks to try

7. Personalization

There is no doubt personalization is important in content. However, you have to make it relevant.

Adding only the recipient’s name won’t necessarily increase your open rates if your audience receives similar emails from other brands. Test your subject lines by adding other particulars like geography, preference, birthdays, or anniversaries.

Take care not to include too much info as it may make you look snoopy. Let’s see this in action.

As you can see, the two emails are highly personalized, reminding users of an offer, probably designed only for them. This is a great way to improve open rates and engagements.

8. Numbers and lists

There is something that numbers have that other variants lack. It provides some visual jolt and a promise of what to expect. It is no wonder that the top ten and hundred lists attract lots of attention, and blogs that have numbers in their titles generate up to 206% more traffic than those without.

Similar results can also be replicated in the email subject line with numbers. You can include numbers and lists in your email subject lines and find the right balance to implement.

Here are a few examples of the use of numbers in subject lines.

Do you see how the numbers in the above subject lines are tantalizing, promoting one to click through and find out what the deal is all about?

How to A/B test email subject lines?

Before you test or pick a parameter, there are some best practices to keep. This will help you weed out less important results or details early in your campaigns.

1. Decide what subject line to test

You cannot test every subject line. The time and resources won’t support it.

Two, you may end up with a long list of results that you won’t know which to pick or implement in your email marketing campaigns. Select one variable to test in each campaign. To find the variable to test, identify:

  • Your goals or what metrics are you tracking — is it conversion or open rates?
  • Your audience
  • Tools to use

After that, you can pick a variable to run a split test.

2. Determine your goals

A few goals to achieve at the end of your campaign include.

  • Understanding what audiences respond to emails
  • Find the best time to send emails
  • What offers are more likely to attract your audience
  • The tone of voice to use
  • What subject lines improve open rates

Whatever it is, identifying your goals will set you up for success with your campaigns.

3. Establish benchmarks or how to measure results

Setting benchmarks may require you to look at the previous campaign and how you fared on them. Use that data to analyze your A/B test and gauge your success before launching the campaign.

These historical data and benchmarks should also help you determine what variables to A/B test. Besides, it would help you determine your goals or objectives. Hence choose something measurable.

4. Determine your test sample

If you have a highly niched audience or small subscriber base, you may test your campaigns on every subscriber to collect adequate data. If not, segment your market or subscriber list before you run a split test.

Choose the correct sample size that would give you enough data and accurate results. You may go back at your goals and historical data to determine what sample size to test.

5. Establish how long the A/B test should run

How long should the A/B test run? To find out, consider your resources and goals. Make use also of the A/B testing significance calculator to find the confidence levels of your test result and implement it in future split tests.

For a first-time campaign, aim to get statistically significant results before ending the campaigns.

Then you can start analyzing and taking records of what improved, plateaued, and the identical patterns that have repeated themselves. Noting a detailed account of what has happened will help you in your future email optimization campaigns.

Wrapping Up

If you want to remove assumptions or uncertainty in your email subject lines or want to find how you fare at your prospect inboxes, A/B test your email subject lines.

There are lots of parameters you can test. Testing your email subject lines will give you real, powerful, and straightforward insights and remove the guesswork in your email campaigns.

Testing your email subject lines will help you make better decisions in your email optimization campaigns and improve open rates and conversion.

Email lines source: reallygoodemails dotcom

Image Credit: markus spiske; pexels

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The ReadWrite Editorial policy involves closely monitoring the tech industry for major developments, new product launches, AI breakthroughs, video game releases and other newsworthy events. Editors assign relevant stories to staff writers or freelance contributors with expertise in each particular topic area. Before publication, articles go through a rigorous round of editing for accuracy, clarity, and to ensure adherence to ReadWrite's style guidelines.

Adela Belin

Adela Belin is a content marketer and blogger at Writers Per Hour. She is passionate about sharing stories with the hope to make a difference in people's lives and contribute to their personal and professional growth.

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