[Campaign Analysis]: How Can You Improve Your Email Marketing Performance by Optimising Your Subject Lines?
How many promotional emails do you receive every day on an average?
You may not be able to answer that because you probably don’t even look at them before pressing bulk-delete. However, the few emails with catchy subject lines do manage to grab your attention, right?
This is how most email users behave today, which is perfectly justifiable given the huge number of emails they receive. But for marketers like you, this user behaviour is not desirable. As a result-oriented marketer, you would want your users to open and click the carefully crafted emails you send them.
Out of the many factors that influence email open rates, the quality of your subject lines is critical.
Related: Check out Smartech’s AI-powered features to boost your email marketing.
Here at Smartech, we analysed over 2 million emails, to find out how email campaign performance can vary on the basis of your subject lines.
For goal-oriented email marketers like you, these are the key factors that need to be kept in mind to help you optimise your email subject lines to deliver high conversion email campaigns:
Factor #1: Length of the Subject Line
The length of your subject lines is an open secret - the shorter the better. We found that promotional email campaigns with subject lines with more than 50 characters fared poorly than the ones that have shorter subject lines. Since people check emails on their smartphones now, shorter subject lines that are completely visible on the screen tend to do well.
For campaigns where you can’t shorten the subject line below 50 characters, ensure that the gist of your marketing message is conveyed within the visible character limit.
We observed a 23% drop in campaign performance in which the subject lines were longer than 50 characters.
Factor #2: Punctuation Marks
What punctuation do for your email campaign subject lines, gravity does for rivers! It decides the flow.
60% of punctuation marks used in subject lines include the following:
- Period (.)
- Exclamation (!)
- Comma (,)
Usually, subject lines without punctuations perform the best.
Why you may ask?
The absence of punctuation indicates simplicity and higher readability. But, there will be instances where you will have to use punctuations.
Our study revealed that the optimum number of punctuation marks that can be used in an email subject line is 2-4.
Periods do not really influence the open rate, but commas do improve the email performance. Especially 3 commas that indicate a list of items or brands.
For example; 15% discount on bags, wallets, accessories on XYZ Brand
Commas work well. Using commas shows a 4% uplift in open rates. Using multiple commas indicating listed items showed further improvement in campaign performance.
Using question marks in the subject line show a dip of 4% in the open rate.
Also, exclamation marks do more harm than good, may be due to the clutter they cause.
A subject line with both question mark and exclamation mark affects the campaign performance negatively. In fact, the PLING_QUERY Rule is a directive by the Apache web server that considers an email as spam if its subject line includes a question mark as well as an exclamation mark.
However, there are always exceptions to the norm.
Something like “SALE! SALE! SALE!” is something that has always worked!
Just like colours, images, and keywords impact a user’s psyche, punctuation marks in your email subject lines can make your users feel differently. These can mean the difference between your email being opened or ignored.
Factor #3: Tags/Keywords
Using certain words in your subject lines affects the way users treat the emails. For instance, subject lines that have the word ‘discount’ in different forms still continues to find favour with customers, resulting in an open rate uplift of 12% compared to normal campaigns.
Including specific brand names in the subject line leads to better email marketing campaign performance. Subject lines conveying urgency and scarcity tell readers they must act now, creating an instant sense of FOMO (Fear of Missing Out!)
“15% discount on Reebok shoes!” has more potential to attract users as compared to a generic “15% discount on sports shoes”
Of course the popularity of a brand also has an impact on the open rates.
Today’s highly distracted users think twice about the time and effort required to open an email. So, it becomes all the more important to be as informative as possible within your subject line itself. Your subject lines need to get them “hooked” right at the onset.
Our study suggests that subject lines that give information have constantly outperformed mere curiosity-inducers.
However, a word of caution - if your subject line gives away all the information, you might invite direct dismissal because there's nothing left for the user to discover. So, maintain the balance. Save critical content element for the actual email body so that the user feels enticed to open the email.
Think of subject lines as an engaging “trailer” to your actual “film”!
Surprisingly, the word “FREE” has lost its charm. Subject lines like “Free tickets for you”, “Free coupons” etc. show a 15% dip in open rates.
This is possibly due to the sentiment of mistrust that the word now evokes in users, given how overused and abused the word has become in marketing communication over the years!
Factor #4: Personalisation
The traditional personalisation technique of addressing users by their first name is still appreciated. Such subject lines show 6% better performance as compared to campaigns with impersonal subject lines.
“Sid, check out these hand-picked shoes!” strikes a personal chord with user right at the onset.
Apart from name personalisation, the content of the subject lines can also be personalised based on your users’ historical behaviour and interactions with your previous campaigns.
Check out AI-powered subject line optimisation to help you craft hyper-personalised subject lines guaranteed to elevate your email marketing performance!
Factor #5: Emotions
Every campaign carries a certain emotion attached to it. And, subject lines play a crucial role in invoking that emotion.
For instance, an enticing subject line like “Mouth Watering Deals, Coming Your Way!" invokes excitement and anticipation.
“Sid, we safeguard your data” generates a feeling of mutual trust.
However, using positive words all the time can become repetitive, boring, and bland. It's essential to experiment with quirky and negative terms/idioms to eventually create a positive message.
For instance, “Get Lost!! In the big bonanza summer sale.” has a light-hearted flavor to it.
Our study showed that negative idioms combined with witty phrases boost open rates by around 2%.
By leveraging the power of A/B testing, you can analyse how the user responses vary to different subject lines.
Factor #6: Emojis
Using up to 3 emojis in the subject line shows a 15% increase in campaign performance.
But, anything more than 3 emojis impacts performance negatively, because the use of too many emojis can eat into your character limitation and cause needless clutter.
"Using emojis can increase open rates by almost 15%."
Better Subject Lines = Better Email Campaign Performance
With the advent of AI in marketing technology, creating click-worthy, high conversion email marketing campaigns is no longer just intuition and creativity driven. It is now driven by user behavioural data insights as well. By focusing on the above highlighted factors, you can hit upon the right best practice mix to optimise your email subject lines. Don’t think of your subject lines as just eyeball-grabbing hooks. Think of them as laying the foundation for better conversions, user engagement, and retention.
To know more about the AI-powered features that can help you take your email marketing programme to the next level, get in touch with us, today!
Saurabh is a Data Scientist at Netcore. When not analysing data, he likes to play with cats & dogs.
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