Here is an excerpt from an article written by Jill Flynn, Kathryn Heath, and Mary Davis Holt for the Harvard Business Review blog. To read the complete article, check out the wealth of free resources, and sign up for a subscription to HBR email alerts, please click here.

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Having combed through more than a thousand 360-degree performance assessments conducted in recent years, we’ve found, by a wide margin, that the primary criticism men have about their female colleagues is that the women they work with seem to exhibit low self-confidence.

Our gut says that this may partly be a perception issue — we’ve observed that men sometimes interpret (or misinterpret) an inclination in women to share credit or defer judgment as a lack of confidence. Still, perception or not, there is some research to suggest that women themselves feel less self-assured at work than men. A study released in 2011 by Europe’s Institute of Leadership and Management revealed that women report having lower confidence in regard to their careers:

Men were more confident across all age groups, with 70% of males having high or very high levels of self-confidence, compared to 50% of the women surveyed.

Half of women managers admitted to feelings of self-doubt about their performance and career, but only 31% of men reported the same.

The study also found that this lack of confidence extends to a more cautious approach to applying for jobs and promotions: 20% of men said they would apply for a role despite only partially meeting its job description, compared to 14% of women.

Looking back through scores of interviews we’ve conducted in the course of training and coaching engagements, and returning to the 360 reports, these are the four specific low-confidence behaviors cited by managers (male and female alike):

Being overly modest. We see that men are more willing to take public credit for their successes. Women believe their accomplishments should speak for themselves, and they spend less effort ensuring they get the gold star next to their name. While modesty is a nice character trait, it’s naive to believe that your boss, your clients, or your colleagues will recognize your accomplishments if you fly under the radar.

Not asking. We’ve seen it over and over again: women fail to get promoted because they fail to step up and apply. It feels personally risky to step-up and ask for a big job or assignment — but there’s really no other way. Not asking means you’ve lost the chance to influence the outcome.

When Sharon Allen became chairman of Deloitte & Touche USA in 2003, she not only became the highest-ranking woman in the firm’s history, she also became the first woman to hold that role at a leading professional services firm. It may seem surprising, then, that even Allen learned this lesson the hard way. As a rising manager in her thirties, she was taken aback when she received a memo announcing the promotion of several close colleagues. She wondered why she didn’t make the list. Allen stewed about it for a day or two, and then went in to see her boss.

“I was surprised to see my name not included on the promotion list,” Sharon said to him. “I have accomplished A, B, C, D and E and I think I deserved that promotion.” Her boss replied, “Sharon, I had no idea you had accomplished all of those things. You didn’t let me know.” When Sharon tells the story today, she laughs and shakes her head. As she told us, “That’s the very last time I ever let that happen.”

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Flynn, Heath, and Holt then share their thoughts about two other specific low-confidence behaviors cited by managers (male and female alike): Blending in and Remaining silent. To read the complete article, please click here.

They  nationally recognized experts on women’s leadership and principals of Flynn Heath Holt Leadership (FHHL) as well as co-authors of Break Your Own Rules: How to Change the Patterns of Thinking that Block Women’s Paths to Power.