Email etiquette is so confusing these days.

In some workplaces - included - communicating in GIFs and emojis is socially mandated.

PR agencies are notorious for their chirpy use of the opening line "I hope you're well", while lawyers and accountants take a more formal approach.

And when it comes to signing off from professional correspondence, you could be forgiven for thinking that anything goes.


But if you want your email to get a response, there is a specific formula proven to increase your chances.

According to a new analysis from email productivity app Boomerang, there's one simple trick that makes people more likely to write back: expressing gratitude.

After crunching the numbers on more than 350,000 email threads from mailing list archives, researchers found that the most effective email sign-off was "thanks in advance", Boomerang revealed in a blog post.

"Closing with an expression of gratitude correlated with a whopping 36 per cent relative increase in average response rate compared to signing off another way," the researchers said.

On the other hand, ending your email with "best" was the least effective approach, yielding the lowest average response rate when compared to the other seven options.

The emails analysed were those in which people were seeking help or advice, and hoping for a reply.

Out of the eight most common sign-off phrases, the results were as follows:

• "Thanks in advance" had a response rate of 65.7 per cent
• "Thanks" had a response rate of 63 per cent
• "Thank you" had a response rate of 57.9 per cent
• "Cheers" had a response rate of 54.4 per cent
• "Kind regards" had a response rate of 53.9 per cent
• "Regards" had a response rate of 53.5 per cent
• "Best regards" had a response rate of 52.9 per cent
• "Best" had a response rate of 51.2 per cent

The average response rate for all of the emails in the sample was 47.5 per cent.

In its blog, Boomerang referred to an earlier research paper that found participants who received an email from a student asking for feedback on a cover letter were twice as likely to help if the student wrote: "Thanks so much! I am really grateful."

The 2010 study, published in the Journal of Personality and Social Psychology, found that gratitude expressions made people feel more inclined to help others because they boosted "communal feelings of social worth".

"Gratitude expressions are likely to influence how helpers view themselves in the social world," the researchers wrote, explaining that such messages increased their recipients' feelings of personal competence, self-efficacy, interpersonal warmth and connectedness to others.