All leaders have their blind spots, those disconnects between how they think they are showing up in the world and how their employees perceive them. Across hundreds of interviews with CEOs about the key leadership lessons they’ve learned, one of the most consistent themes we’ve heard is their growing recognition that they must make an extra effort to close the gap between how much they think they need to communicate and what their employees want and need from them.

It is one of the key principles of leadership: There is no such thing as overcommunication. All leaders have to repeat the strategy relentlessly and remind employees of the “why” behind the work they are doing, no matter how redundant the messaging may feel to them.

“At first, I wondered how many times I’d have to say the same thing,” said Andi Owen, chief executive of Herman Miller, the office furniture company. “Then I realized that there are eight thousand employees, and in almost every venue I’m in, people are meeting me for the first time. I have to repeat the core message over and over because my job is to set the direction, communicate, and be inspiring. I thought I would spend a lot more time doing some other things, but most of my day is spent communicating.”

Owen’s insight was echoed by Christopher Nassetta, the CEO of Hilton Worldwide. “You have to be careful as a leader, particularly of a big organization,” he said. “You can find yourself communicating the same thing so many times that you get tired of hearing it. And so you might alter how you say it, or shorthand it, because you have literally said it so many times that you think nobody else on earth could want to hear this. But you can’t stop.”

The need to constantly remind people of the strategy can seem puzzling. After all, people are smart, and presumably they can remember the key components of a simple plan from week to week.

One answer is captured in an insight from Marcus Ryu, the chairman and cofounder of Guidewire, which makes software for the insurance industry. “I’ve come to realize that no matter how smart the people are who you’re communicating to, the more of them there are, the dumber the collective gets. And so you could have a room full of Einsteins, but if there are two hundred or three hundred of them, then you still have to talk to them like they’re just average people. As the audience gets bigger and bigger, your message has to get simpler and simpler, and the bullet-point list has to be shorter and shorter.”

A second reason why repetition is so important is that businesses, just as in nature, abhor a vacuum, and if leaders aren’t saying anything, then employees will supply their own narrative, and they will often go to a dark place, spinning conspiracies or worst-case scenarios. Uncertainty creates free-floating, contagious anxiety.

“People read a lot more meaning into things that you didn’t necessarily intend to have meaning,” said Christy Wyatt, the CEO of Absolute Software, a cybersecurity company. “People will make up stories in the white space.”

One vivid reminder of this rule played out when she was leading another firm, called Good Technology. Like most Silicon Valley companies, it had a kitchen stocked with free snacks and drinks. The company decided to switch the vendors that supplied the snacks, so there was a week when supplies ran low before the new vendor took over.

“[Since] we hadn’t said anything about it, and the food was starting to run low, people started saying, ‘There’s layoffs coming; bad things are going to happen,'” Wyatt recalled. “I actually had to say in an all-hands meeting, ‘Guys, it’s just the nuts in the kitchen. That’s it.’ But people look for symbols, and they look for meaning where maybe there isn’t any. So now we’re overcommunicating.”

Finally, leaders must be prepared to be teased for endlessly repeating the strategy. If your employees roll their eyes and say what you’re going to say before you open your mouth, consider that a victory because they have internalized the message. Getting to that point requires far more communication than you might think, and in all forms—all-hands meetings, email blasts, webcasts. All these approaches are necessary to fight the collective short attention spans in organizations.

“You tell people, ‘Here’s where we’re headed and these are our priorities,’ and then you just sense how often people are wandering,” said Laurel Richie, the former president of the Women’s National Basketball Association. “I always say that part of the job is keeping all the bunnies in the box. You start with all the bunnies in the box, and then somebody gets a great idea to go do something else, and you go help them all come back and get in line, and then a bunny over here pops out. So the more the bunnies are getting out of the box, the more I realize I just haven’t done a good enough job communicating what our priorities are and what our focus should be.”

For leaders at all levels, the lesson is clear: When in doubt, say it again.

This article adapted from Bryant and Sharer’s upcoming book, The CEO Test: Master the Challenges That Make or Break All Leaders, releasing with Harvard Business Review Press March 2021.

Adam Bryant is managing director of Merryck & Co., a leadership development and senior executive mentoring firm. He was a journalist for 30 years, including at The New York Times, where he created and authored the widely read “Corner Office” column, for which he interviewed more than 500 CEOs and other leaders.

Kevin Sharer is the former president, CEO, and chairman of Amgen, the world’s largest biotech company. He also taught strategy and management at Harvard Business School for seven years.