Practical Ecommerce

To Optimize Email Marketing, Test These 3 Elements

One of the best things about email marketing is the ability to test elements in a campaign and quickly receive actionable data. Moreover, the results of email tests can apply to other marketing efforts or to a website generally.

Testing for email marketing is typically done in one of two ways.

  • A/B test. This is simply when you divide your file into equal segments and each segment receives a different version of the element you are testing. It can be more that two segments, so long as the test size is statistically significant.
  • Percentage test. This is when you test a percentage of your file, say 20 percent, which is then divided by the A/B segments. The test is run for finite time, perhaps 6 hours, with a method of determining the winner based, typically, on the number of opens or clicks. When the winner of the test has been established, the remaining portion of the file will receive the winning version. This tactic is good for optimizing within a single deployment. Many email service providers have automated testing platforms.

In this post, I’ll explore three email-marketing elements to continually test, to optimize their performance.

Subject Lines

An email is effective only if people open it. Testing your subject lines constantly can greatly optimize your email marketing. Test subject lines on different segments to determine how subscribers respond, on the following metrics.

  • Open rate. The higher the open rate, the better the subject line. However, consider this metric in conjunction with other metrics — such as click-to-open rate and conversion rate, discussed below — to know how successful the subject line was.
  • Click-to-open rate. This measures the percentage of recipients who opened the email and then clicked on it. This metric is important, as low click-to-open rates will help identify catchy subject lines that produced few conversions.
  • Conversion rate. Conversions are the ultimate goal of most email marketing campaigns. Low conversion rates suggest a more direct and actionable subject line is needed, to inform subscribers of the action you want from them.
Changing the subject line can affect recipients' behavior. In this example, using "See if you qualify" instead of "Apply" led to significant increases in open and click rates.

Changing the subject line can affect recipients’ behavior. In this example, using “See if you qualify” instead of “Apply” led to significant increases in open and click rates.

Offer or Call to Action

Every email-marketing message should have a specific goal or objective. Perhaps you are communicating new products for subscribers to browse, or you are promoting discounted items. Regardless, an email’s design and call to action or offer should reflect its objective. Testing multiple offers or calls to action will help you understand your subscribers. For instance, some subscribers react to deadline-oriented offers while others respond to discounts.

This creative showcases two different offers the advertiser is testing. The example on the left emphasizes the promotion of "20% Off" much more prominently.

This creative showcases two different offers the advertiser is testing. The example on the left emphasizes the promotion of “20% Off” much more prominently.

Day of Week and Time of Day

Prior to widespread mobile adoption, email engagement followed a typical 40-hour workweek: people opened and read emails at their work computers. Today, many brands see the highest engagement on nights and weekends. Regardless, testing and optimizing the deployment day and time can help boost open, click, and conversion rates.

Carolyn Nye

Carolyn Nye

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  1. Jamie February 17, 2017 Reply

    Thanks for the article Carolyn.

    You mention communicating new products or discounted items under the call to action header, and I agree that this is a great reason for sending newsletters. It could be better to communicate other company’s products though instead of your own… hear me out.

    By partnering with carefully selected online merchants, a marketer can send newsletters that offer great deals on products that the email recipient will appreciate. An email that is appreciated will obviously help to build your brand and encourage them to do more business with you.

    You wouldn’t be doing it entirely through altruism though, of course, that would be marketing suicide. Those partners that you are advertising for? Well, in return, they will be helping to advertise YOUR relevant products on their newsletters. While you’re scratching your partner’s backs, they’ll be scratching yours and you’ll be helping each other to make new customer acquisitions and generate revenue directly.

    • Keith February 21, 2017 Reply

      I’ve wondered about partnering but haven’t tried much & the results were dismal on Facebook. And subject lines are a tough one too, coming up with something interesting enough to catch a customers attention. There are even subject line creator websites that will take your keywords & munch them up and spit them out – in subject lines. is at least kinda humerous with their attempts.