The Psychology Behind Subject Lines and Open Rates

Subject lines. Open rates. They're integral parts of email marketing, and it's no secret that a good open rate is vital to a successful campaign. Time can be spent crafting an amazing email with incredible graphics and clever copy, but if nobody actually opens it, what's the point? That's why strong subject lines are of crucial importance. But how do you write a good subject line that will influence people to click? 

We have to understand that people judge an email like they judge human beings: in mere seconds. It's in our nature to make snap judgements. That's why subject lines under 40 characters can be helpful. The pre-header text, which complements the subject line, is your opportunity to showcase a great deal, perhaps, or at least something meaningful to your email campaign.

What constitutes a good subject line, anyway? A good (or even great) subject line will do more than just snag someone's attention—it will completely pique curiosity. Human nature gives us a need to answer questions, as questions stimulate the neocortex, a part of the brain that is in charge of spatial reasoning, conscious thought, language, sensory perception and generation of motor commands. However, the question or problem your subject line poses must be relevant to the content it links to; otherwise, your customers may feel cheated.

Promotion of exclusivity in a subject line touches on the theory of Maslow's Hierarchy of Needs, a five-tier pyramidal depiction of human needs that drives motivation, in which esteem sits near the top—our need for status and prestige. To appeal to this need, a subject line may read, "Just for you…" or "Your exclusive, limited-time offer." There are four other needs you can appeal to in an email, however, including physiological, safety, belonging and self-actualization.

Personalization is also another great tool to utilize. By using "Don't miss these deals, [Name]" instead of just "Don't miss these deals", you can offer your customers a more personalized experience with your brand. Personalization works because of what psychologists call "The Cocktail Party Effect." What this means is that we have the ability to tune out almost all noise in a crowded room except when we hear something that's personal or somehow relevant to ourselves—like our names.

There are a lot of factors you can take into consideration when constructing a subject line, but here's something you can do that may help overall: consider what would compel you to open a marketing email and think from a customer's or consumer's perspective. For example, this subject line, which touches on Maslow's theory of human needs, had a 46% open rate this past September: "Just for you: new specials." "Do you have plans this weekend?" had a 36% open rate.

What constitutes a good open rate will depend on your industry. According to Constant Contact, the marketing industry has an average open rate of 12.11%. The overall average for all industries, as of June 2019, is 14.79%. There are other factors that can affect your open rate, such as targeting (sometimes called segmentation) or your individual spam rating with both the individual subscriber and the email provider. By segmenting your lists, email campaigns (and, in turn, subject lines) can be better tailored to the individual group's needs or wants. Your open rate is also affected by the bounce rate, or how many emails were undeliverable. Of course, it's important to have great content!

We get it. Crafting a compelling subject line isn't easy. Just remember that your email campaigns are going to humans, so think like a consumer.