Do you suffer from a crisis of confidence? Your answer to that question may depend on whether you're a man or woman. Despite the fact that women represent more than 50 percent of U.S. college graduates, a new book by journalists Katty Kay and Claire Shipman, "The Confidence Code: The Art and Science of Self-Assurance – What Women Should Know," says women lack one key element that is holding them back from climbing the corporate ladder and achieving greatness: confidence. 

The fact that Kay and Shipman, who both appear as strong, competent women on television, say their careers have been plagued by self-doubt and a lack of confidence, is shocking. Shipman spent five years reporting from Moscow for CNN and is now a regular contributor to Good Morning America. Kay, a news anchor for BBC World News America, has covered three presidential elections, and wars in Kosovo, Afghanistan and Iraq. "I have spent years saying to younger students [who] asked me how I got to where I am, ‘I was just in the right place at the right time’," says Kay. 

Through interviews with other high-ranking women, Kay and Shipman found chalking success up to dumb luck rather than a result of hard work and talent was incredibly common. Yet men in powerful positions didn’t appear to have confidence issues at all.

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So, why do women, more than men, suffer from a crisis of confidence? 

Women are more likely to be perfectionists. A personnel study by Hewlett-Packard found women only applied for a promotion if they met 100 percent of the requirements, while men felt comfortable applying even if they only met 60 percent of the requirements, feeling they could learn the rest on the job. "[Women] think we have to be perfect, or almost perfect, before we go for things," says Kay.

A study at Columbia University found men routinely overestimated their abilities by 30 percent while women routinely underestimated their abilities. "We are holding ourselves back because we're doubting our ability to succeed," says Kay. Striving for perfection, leaving no room for failure sometimes, will always leave us lacking and kills women's confidence, she says.

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Women are more prone to ruminate, over-think and analyze. Although men can have self-doubts as well, Kay says they don't beat themselves up the same way as women do. She gives the example of a situation where she asked a "less-than-smart" question during an on-air interview. "That was at 6:30 in the morning and I was still thinking about it at 6:30 that evening and the next day," says Kay. Carrying criticisms for hours, days and weeks, Kay says, weighs on women's minds and stands in the way of success. She argues women need to get better at letting our internal criticisms roll off us in order to boost our confidence.

Women let their nerves prevent them from acting. Kay and Shipman define confidence as “the thing that propels us to take action." Confidence is what causes us to raise our hand in a meeting, to stand up to a colleague we disagree with, to introduce ourselves to a stranger at a party. While men and women both experience nerves, Kay says women tend to let their nerves stop them from taking action. 

Kay gives an example of a meeting she attended at the White House where she was one of two women in a group of 14 male Middle East experts. When the Q&A portion of the meeting commenced, the men jumped in with their questions. Thoughts of self-doubt crept into Kay's consciousness. "I'm thinking if I ask a question it's going to be stupid, and they'll realize I don't know as much as they do, and then I’ll be stammering and I have this internal dialogue going on in my head about the risk I’m about to take," she says. Kay worked up the nerve to put up her hand and ask a question. "It wasn’t the smartest question in the history of questions but it wasn’t totally dumb, I didn’t fall on my head and the earth didn’t swallow me whole," she jokes. 

The key to growing confidence in women, she says, is to go into situations that force them to confront their nerves. "The next time around when I was in a similar [nerve-wracking] situation, it was much easier because I had the confidence that I'd been through that situation before and survived it," says Kay. 

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