Just as when you have been invited to have a meet with the big dogs and big names in society. At that meet, you would meet the people that matter who can help make or mar your career. You need to be at your best and dress your best.

You test out several different outfits to ensure you get the perfect one. This is just about the same with testing the email selecting good subject lines. There are benefits to these things so it is important you get them tested as they have their obvious advantages.

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First of all, just before we dive in, we should have a look at why email subject lines are important. 

The Importance of Email Subject Lines 

As a professional in marketing, you would know how vital it is that you create a strong and captivating email subject lines. These go a long way in helping you woo your audience in the first place. However, you have to understand how to make your email dynamic in all areas and also its subject line. 

Normally, people receive tons of emails daily and it takes a catchy subject line to make a person decide on whether or not to open the email (learn more about open rate in our article 11 Essential Tips to Increase Your Email Marketing Open Rate). This then means that a lot of things are therefore being determined by the email subject lines.

You can’t just expect to trust instinct or intuition. You need to gather as much information, make enough research. You would also need to test subject lines to know what type catches the attention of your audience enough to make them read messages. Here are a few ways through which you can test your email subject lines.

Choosing Your Audience Segment 

One thing you should know is that you can never please everyone so you should never try to. You don’t need to get the most unique line ever used but it is for you to try getting subject lines that flows well with your unique audience and customers. One way to achieve that is by targeting a specified audience segment. 

Someone running a campaign for a school election or anything of the sort would need to send messages to his various audience types. He might want to address some students who require loans and another to concerned parents. These emails cannot have the same subject line and would be best to send one type of mail to those in need of student loans. Another type, to those concerned parents.   

You need to think about what type that speaks most to your audience segment and then brainstorm on getting those subject lines.  

You can segment your clients according to: 

  • Age
  • Income
  • Geographical location 
  • Profession 
  • Previously purchased item 

And so much more. The method with which you use to segment your clients varies and is majorly dependent on your lime of work/product or service provided and your clientele. 

Make a decision on what aspect to test

Sometimes one can get that split-testing fever and then feel like testing every subject line they come across. The best way to get an accurate result is by A/B testing of subject line. Try resisting the urge to do them all at the same time. 

When testing, there are some things you should check out for as they play a huge role in helping you get your desired result. You should always check out:

  • The personalization
  • Length
  • Word
  • Design or style 

These four attributes affect the outlook of your subject line and play a role in determining whether they are attractive, catchy, or not. 


The personalization mainly has to do with the intimacy of your relation with your client. Many companies feel personalization is “Dear [INSERT NAME HERE]” but it goes further than that.

It goes all the way to relating previous actions of said client, indicating promos or advertising things that are available in their general location of said client etc. This form of personalization builds a relationship with the client by giving them a sense of ‘oh I actually matter to these people, they are interested in who I am’.


A subject line should be long enough to convey a message and short enough not to bore readers. 


Nobody enjoys unnecessary stretch of vocabulary and no one is going to open a dictionary to understand a subject line unless it’s from the word of the month club. Your email subject line should be understood by a layman but not tacky. 

Design or style

A lot of e-mail marketing strategists believe that creative font is eye catching and more likely to make people read to the end. You would have to study style in email marketing and subject lines to effectively utilize a style that is right for you. 

Test a Part of Your List 

If you have a large or big enough list containing some credible samples and sizes, then you should consider testing just a part of it. By testing in portions or parts, you can then decipher what subject line would possibly give the best result. Then you can add it to your main list. A few people like testing the entire list; this is great when you have a small list compared to one with a longer list.  

Subject line testing is now more important than ever and that is why the testing of every line is important. You can endeavor to split your email list into various segments and try sending a very different line to each of your lists. You can have two or three segments depending on your choice. 

Try ensuring you send both lists about around the same period. It may be around the same time but certainly on the same day. This can help you remove those unwanted lines from your comparison or list.  

Analysis of Every Data

At this time, results are in and its time to get down to work. It is time for some analysis. If you are a data freak, then this is just the time you have been waiting for. Once the data comes in, the next step is to analyze each one. While analyzing each one of them, never forget to keep your mind focused on the actual goal ahead (more about this in our article 10 Essential Email Marketing Metrics).

Of course, open rates and click-through rates are important. Actually, it is an undeniable fact but still, conversions are always going to stand out as the most important. The fact that a particular subject line happens to have a high number of open rate does not mean it will also have the most conversions or the most click through. 

Ensure you dig deeper and deeper in your analysis. Try bringing out a lot of important and intriguing data. Every data is vital no matter how small it might seem. While testing you might find out that one subject line would gather a higher overall opens.

Another might have more opens from the audience within the age range of 30 – 35 years. All data should be analyzed as they would all prove useful.  

Don’t Stop Your Testing Process

Testing for subject lines is not a one-time thing. You don’t just test once and then you do because you think the results are perfect to work effectively for a long time. No! It doesn’t work like that. The basis of having a steady, solid marketing and a good subject line performance is constant and regular testing. Your last test might have taught you about the length of the subject line preferred by your audience, next time; you test on either the personalization or the design. There is always something to test. 

One thing which is always constant is change. People change and their taste also changes with time. Your audience might be used to your type of subject line and then start ignoring them after a while. This is why you need to switch things up and it can only be done perfectly after good testing. 

For every time there is a communication between you and your audience, it is an avenue for new testing. A chance to improve your messaging strategy. The more your communication is improved, the more chances you have of being rewarded with higher clicks.  

Great emails and messages are not built on instinct. Rather they are built on data analysis and experience. You need to always keep testing your email subject lines to make sure they are what your audience wants to see and to help you switch things up easily. 


Email subject line testing is one of the best things you can use to improve your marketing and your communication with your audience. This will help you get a better understanding of what your audience love and in turn, help you improve your business. 

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