Emails vs letters. What works, when and why

At BehaviourWorks, we’re often asked: “Should I send emails or letters?” There isn’t a right answer to this question – it always depends on the factors at play.

In this article, we explore some of these factors to help you to make better decisions and discuss some persuasive strategies for written communication.

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Comparing emails and letters

Letters and emails are different communication channels with different qualities.

To make these qualities clearer, let’s compare letters and emails in three ways:

• i) what they can do (that the other can’t),
• ii) how we engage with them, and
• iii) what they achieve.

What each can do (that the other can’t)

Compared to emails, letters can, for example:

• Reach target audiences that don’t have email.
• Have a tangible physical ‘presence’ that will hold attention for longer.
• People often keep letters for months, but process and discard emails very quickly.
• Gain appreciation or prompt a desire to reciprocate.
• Provide physical gifts and supplements alongside the information.

How we engage with them

Here are some relevant differences in how people engage with emails and letters.

• When people open letters, they are usually focusing all attention on the letter. In contrast, when people open emails, they are more likely to be distracted. For instance, they may be aware of other emails on their screen.
• People have consistent expectations of the length of letters. Letters are usually one size. The letter-opener is therefore prepared to read a full letter when they get one. An unopened letter won't appear to be longer if we add a persuasive strategy. Usually it will be opened and read just as much. In contrast, people vary more in their expectations of the length of emails. Short emails are common and emails don't come in a standard window, so their length is even more noticeable. If emails are longer, then the reader needs to scroll down the screen to get through them. The reader is therefore more likely to ignore or abandon longer emails.
• People open emails based on the source and subject line. People will be much more likely to read your email if it comes from a good and credible source, than if it doesn't. In contrast, letters give you much less information about who they are from or what they are about before they are opened.
• People probably value receiving a handwritten letter or card more than getting the same information digitally because it feels more tangible, unique and thoughtful. Letters have an emotional power that comes from being more tangible and material than digital communication. It’s hard for us to overcome our need to touch and feel something. There is a somewhat related famous example, popularised by Robert Cialdini of Joe Girard, the world's best salesman, who apparently sent a card to all of his customers each year.
• Many people appear to find writing a letter to be more emotionally stimulating than typing or texting. This may be because it's a much more physical, personal and tangible act of creation than typing something out, and you don’t have to face the same distractions that come with using a device.

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How we measure their effectiveness

There are many different metrics for assessing how communication is performing. With letters, you can measure outcome factors, such as:

• Reception rate – did people get the letter?
• Open rate – did they open the letter?
• Recall rate – did they remember the letter.
• Response rate – did they respond to the letter?
• Compliance rate – did people do what the letter asked.

With email, you can often measure more outcomes, such as:

• Read rate – did they read the email?
• Engagement time – how long did they spend reading the email?
• Click-through rate – how many people clicked a link provided in the email?

It’s easier to measure metrics for email than it is for letters. This is an important consideration for pilot-testing, monitoring and evaluation. For example, with email you can track the percentage of intended receivers who:

• i) received the email
• ii) opened the email
• iii) engaged with the email in some way, i.e.:
• iv) shared it, and
• v) acted in some way because of it.

This level of analysis is not usually possible with letters.

So, how do letters and emails compare when tested on similar outcomes?

Compared to emails, a higher percentage of letters are opened and responded to. But that doesn't answer our main question. We still don't know if letters change behaviour at a higher rate than emails.

We do know letters cost more to send than emails, but whether they return on that investment is a tricky question to answer. There doesn’t seem to be any high-quality research on this: all the identified comparisons between letters and emails failed to control for confounding factors.

We cannot therefore be sure that differences in outcomes were due to the channels used. Instead, they may be due to differences in the behaviours and populations targeted.

So, what are the implications?

Even without concrete numbers around which method is more effective when it come to behaviour change, there are some implications to consider when choosing between letters and emails:

• Because letters, or direct mail, are less cost-effective than email, it may be best to reserve letters for specific situations. For instance, critical communications, or cases where email cannot be used. Letters may also be best for demonstrating, and might include an annual handwritten letter to a particularly valued contact.
• It may be best to use email for complex and lengthy information as email makes it easier to direct readers to further information.

You can harness the benefits of both emails and letter by using both together:

• If you want to save costs, you can send a first wave of emails to prompt a response from all supportive parties. Then you can follow up with a letter to convert those who missed or didn’t respond to the email.
• If you have an urgent and well-funded campaign, you can send letters and emails at the same time. This will ensure that as many people as possible are notified at least once.
• As more mass communication shifts to digital, there may be increasing value in engaging in selected, tangible interactions such as letters.

Adding a persuasive message to an email is somewhat riskier than adding it to a letter. The new content may be persuasive in isolation, however the email’s increased length may cause potential readers to ignore the email or stop reading it halfway through. Be especially cautious if your email is already long or your audience is busy.

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What are some persuasive strategies that can be used on email and letters?

At BWA, we developed a framework called INSPIRE. This framework make it easier to include persuasive strategies within written communication.

The INSPIRE framework outlines several techniques that improve the impact of written communication. Other frameworks, such as EAST, are also widely used.

Conclusion

So, should you send emails or letters? It still depends, but perhaps you now have a better sense of what it depends on – and why. To learn about behavioural science, please check our award-winning content and book.

And if you’re interested in learning more about transforming your written communication skills to get the responses you need from your audience, you may be interested in our INSPIRE framework course. It offers a comprehensive curriculum that combines the latest research in behavioural science with practical tools and techniques for effective communication.