A negative inner voice, one that promotes self-doubt, can hurt your best employees by limiting their potential to grow in a career. Otherwise motivated employees may be hamstrung by their own negative inner voice.

An employee who doubts their ability might sound like a small issue, but the consequences of unchecked self-doubt are harmful to your company.

"If someone on your team is hampered by a harsh inner critic, they're likely to talk themselves out of sharing their ideas and insights," writes Tara Mohr, an expert on women's leadership and the author of Playing Big: Find Your Voice, Your Mission, Your Message, in Harvard Business Review. "Held back by self-doubt, some of your most talented people will shy away from leading projects or teams, or put off going for the big opportunities--new clients, new business lines, innovative moves--that could help your business grow."

As a leader, you see this situation all the time: An employee is assigned a big project, but they say how they aren't ready for such an important task. Or, you introduce a mentee to a powerful contact, but they fail to seize the opportunity.

Most leaders will try to encourage the employee with positive, you-can-do-it type of coaching, but managing another person's self-doubt is a tricky thing. Positive reinforcement will not work, Mohr says.

Below, find out how you can help your employees rise to their potential.

Stop cheerleading.

Mohr says positive reinforcement and compliments don't help to teach employees how to get over self-doubt by themselves.

"You're giving them a fish, but you aren't teaching your people how to fish," she writes. Instead, you should teach your employees how to manage self-doubt on their own by addressing the negative inner voice head-on.

"That's what they really need, because they will make most of their inner-critic driven decisions quickly, in their own heads, without talking to anyone," says Mohr.

Don't fight with the inner voices.

Fighting with someone else's inner voice is a losing battle. "Instead of arguing with your team members' inner critics, you can introduce a conversation about self-doubt--what it is, why it shows up for each of us, and how it can impact what you achieve as a team," Mohr writes.

In your conversation, explain how self-doubt is not a pragmatic or realistic way to think about things and how it "irrationally underestimates" a person's own capabilities. 

To help your employees recognize when their inner critic is talking, tell them to watch out for a track of pessimistic thoughts that focus on problems and how things are impossible. On the flip side, realistic thinking is calm and curious. It focuses on finding solutions, and tries to move things forward.

Manage the critic.

Once your employees are able to recognize when they are in a self-doubting state of mind and when they are being realistic, it's time to teach them how to manage their inner critic.

Tell your employees that self-doubt and trepidation is part of entering a new role and gaining responsibility, but these sentiments shouldn't control their actions. 

"In doing this, you are introducing a powerful new idea," writes Mohr." That readiness for advancement and leadership does not depend on an innate quality of confidence, but rather, on building the skill of managing one's own self-doubts."