“You should be ashamed of your efforts.”

That’s not the sort of thing an employee ever wants to hear. And it’s not the sort of thing a leader should ever want to say, either, even on days when a little tough love is in order. But a study suggests that this kind of negativity isn’t, in itself, the worst kind of leadership.

Lest you take this to mean that you now have license to browbeat and humiliate your workers, however, let’s look at the details.

Knowing what to expect—even if it’s bad—is better than not knowing.

In a study published last month in the Academy of Management Journal, three Michigan State University researchers played the role of supervisors for a group of college students who were assigned a series of stock-pricing tasks. A third of the students were treated fairly for their efforts (“thanks for your effort during the last round”), a third got varieties of that shame-on-you criticism, and a third received a mix of the two. The participants’ heart rates were monitored to determine their stress levels.

The researchers found, as their report says, that “variably fair treatment resulted in greater physiological stress than both consistently fair and consistently unfair treatment.” To put it in plain English: Being a constant jerk to your workers isn’t quite as bad as being an inconsistent jerk to your workers.

Fadel Matta, the lead researcher for the study, told the Washington Post that the findings make sense when you consider that employees are looking for steadiness at the helm. “A lot of it centers around this issue of uncertainty. This notion of knowing what to expect—even if it’s bad—is better than not knowing what to expect at work.”

Let’s be clear, though: Being consistently fair with employees was the best way to keep their heart rates down, as one of the study’s coauthors, Brent Scott, told Science Daily. There’s no need to do a complicated reading of tea leaves to figure out that treating employees well is the optimal way to get good work out of them.

But an important message from the study isn’t so much about whether it’s better to be a “fair” or “unfair” leader as the study defines it—I’ve worked under both types and found reasons to respect both. What the study truly speaks to is trustworthiness, and how easily it can be eroded. Think, for example, of Amazon, a company with a much-debated workplace culture whose core element was an employee feedback tool that was perceived as alternatively a resource for praise and support and a repository for backbiting and scheming. If you must be a bit of a jerk as a leader—and sometimes that’s the temperament, real or perceived—it helps to be what Adam Grant has called a “disagreeable giver,” somebody who can be dislikable but earns the support of those around him or her because the leaders actions focus on supporting them.

In a better world, though, you’re not a jerk at all—not the barky boss, consistently or inconsistently. As chef Mario Batali put it, “yelling is the result of the dismay you feel when you realize you have not done your own job.” Marketing executive Robin Domeniconi coined the term MRI for cultivating a healthy workplace culture—it stands for “most respectful interpretation” of what’s being said in the room. And  trust tends to erode when people fail to consistently interpret their colleagues’ work and statements.

Listening is one part. Self-study is another: The study recommends “prioritizing self-discipline, focus, and careful thinking” for leaders who need a fairness realignment. But the biggest key may be communication: MSU’s Matta tells the Post that one way to mitigate the unfairness problem is to prepare workers for when negative events are in the offing: “Sometimes you have to be unfair…. But if you say, ‘tomorrow this is going to be what’s happening’—then all of a sudden people aren’t coming in not knowing what to expect.”

What do you do to create a culture of fairness, and how do ensure that you’re delivering consistent feedback to employees? Share your experiences in the comments.

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