Email Marketing: Subject line test increases clickthrough rate 18%


Subject lines often have a hefty impact on the success of an email campaign. Yet, marketers rarely have the time for a deep-dive into the psychology of turning interruption into engagement.

In today’s MarketingExperiments Blog post we’re going to take a look at how Jonathan Hosier, Senior Marketing Specialist, MECLABS, used subject line testing to increase clickthrough 18%.

But first, let’s review the research notes for some background on the test.

Background: MarketingExperiments internal testing of Web clinic invitations.

Goal: To increase the open and clickthrough rates for a Web clinic invitation.

Primary Research Question: Which email subject line will generate the highest click rate?

Approach: A/B/C single-factorial split test




When I asked Jonathan about the control, he explained the focus was on identifiers – namely the email’s primary topic and “from” field.

“In previous subject line tests, the control has performed well and enjoyed a healthy reign as a champ for quite some time,” Jonathan explained. “So, it was time put the champ to the test based on new insights from recent research.”


Version A


In Version A, Jonathan explained the idea was to test a previous assumption that more intriguing philosophical questions hold more appeal for the audience. This was based on previous subject line tests where intrigue has outperformed other subject lines.


Version B


For Version B, Jonathan decided to focus on appealing to an internal need marketers have to understand and overcome failure.




Version B outperformed the control by a relative difference of 18.44% at a 99% level of statistical confidence. Version B also saw a 6% lift in open rates over the control at a 99% LOC as well.



What you need to know

The subject line that focused on appealing to multiple internal needs – understand and meeting expectations – outperformed intrigue and simple identifiers.

Although crafting subject lines can be fun at times, the real reward does not rest in the excitement of a few more opens or clicks.

The real reward is in the new discoveries about your audience and how you can connect to their needs on a much deeper level than before.

To learn more about how you can craft subject lines to appeal to internal needs, you can watch the free on-demand MarketingExperiments Web clinic replay of “Subject Lines that Convert.”


Related Resources

A/B Testing for Fun and Profit [Subject Line Writing Contest] – Deadline is Dec. 10

Email Deliverability: Is Gmail’s tabbed inbox a B2B challenge?

Email Marketing: 3 award-winning lessons about relevance

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