If you’ve ever worked in an office, chances are you’ve encountered at least one person who wasn’t called by their real name. Nicknames in the workplace are a pretty common phenomenon, and they run the gamut from describing a personality trait to a worker’s favorite outfit.

Now new research is digging into the impact of using nicknames in the workplace—and when it’s better to abstain.

The study, conducted by researchers Zhe Zhang and Shuili Du and published last Friday in the Harvard Business Review, is called The Rules of Using Playful Nicknames at Work. Zhang and Du polled more than 1,100 U.S.-based adults to better understand the role and impact of nicknames in the office. For their purposes, a nickname is categorized as “giving the named a new identity,” like Space Cowboy for Elon Musk, as opposed to simply shortening a name from Elizabeth to Liz. 

Zhang and Du found that nine out of 10 respondents had either been called a nickname at work or heard one used for someone else, meaning that getting playfully renamed in the office is a fairly ubiquitous occurrence. But they also found that workplace conditions—and who is using the nickname—makes a major difference in how it might be received.

Here’s what you need to know about the rules to office nicknames: 

Using nicknames for your boss could boost morale

Zhang and Du started by asking participants to imagine that they were beginning a new job. Participants were then split into four groups:

• Group 1 was told that employees called their boss by the nickname, Panda, because they always wore a black and white suit.
• Group 2 was told that their boss called an employee by the nickname Panda for the same reason.
• Group 3 was told that employees called their boss by their formal name.
• Group 4 was told that their boss called an employee by their formal name.

Then, the participants were asked a series of questions to evaluate “how psychologically safe, powerful, and respected” they would feel in the imaginary workplace. When participants were told that employees called their boss by a nickname instead of their formal name, they reported that they would generally feel more safe and powerful in that work environment. That’s because employers who would be open to adopting a nickname were viewed as more communally oriented. 

“Consider how nicknames like Mr. 20 Percent for Clive Thompson, former CEO and chair of Rentokil Initial; Pony Ma for Huateng Ma, founder and CEO of Tencent; and Mutti for Angela Merkel, former chancellor of Germany, make you feel about those leaders,” the study’s press release reads. “When someone in a position of power invites others to call them by a nickname, it makes them seem down to earth and in touch with the people around them.”

Bosses, beware: Steer clear of nicknaming your employees

However, nicknames were not universally well-received in this hypothetical scenario. When participants were told that their employer called an employee by a nickname rather than their formal name, they reported that they would feel less safe and powerful. These fictional bosses were viewed as less communally oriented than their nicknamed peers.

“Friendly and well-intentioned nicknames at work do not always lead to better relationships,” Zhang told Fast Company in an email. “Managers and leaders should be cautious about calling their subordinates by nicknames.”

Hierarchy matters

Other variables also impact how nicknames might be received in the office. To test one major differentiator, Zhang and Du ran a follow-up four-group study with an added parameter: level of organizational hierarchy. For this scenario, some respondents were told that their new job involved a strict leadership hierarchy, while others were told that the job had minimal hierarchy.

“The impact of using nicknames was much stronger when participants were told that the workplace was more hierarchical,” the press release notes. “In contrast, when the workplace was described as relatively flat and egalitarian, the impact of using nicknames became much less substantial—or even disappeared entirely.”

Thus, Zhang clarifies, “nicknaming an employee is more harmful in organizations with highly hierarchical cultures because it makes the boss appear even less communal.” Both employees and employers should always make an effort to understand their office culture before using a new nickname.