Amy Edmondson is the Novartis professor of leadership and management at Harvard Business School.

This piece is part of a roundtable with Post columnist Steve Pearlstein and four of our On Leadership expert contributors about the leadership questions surrounding Gen. Cartwright’s pass-over for promotion to chairman of the Joint Chiefs of Staff.

The superficial lesson from the  story of Marine Gen. James Cartwright, who was recently passed over for promotion to chairman of the Joint Chiefs of Staff, is that outspoken leaders don’t win. Yet decades of social science research and the experience of thoughtful leaders in industries ranging from cars to hospitals would suggest otherwise.

 President Obama had the right approach when he initially favored the general’s selection for his courage and integrity to voice dissenting opinions. The pushback from other military leaders, if indeed it was based on this particular aspect of Cartwright’s qualifications, is quite simply wrongheaded. Research on decision-making under uncertainty, in particular, emphasizes the vital role of upward communication and dissenting opinion in arriving at sound conclusions and shaping strategic action. Take for example Yale Professor Irving Janis’s seminal study of decision-making in the Kennedy White House during the Bay of Pigs deliberations. It pins the blame for the fiasco on the failure of several presidential advisers to speak up with grave concerns they held about the invasion. This still-infamous, even 50 years later, foreign-policy failure could have been avoided with greater willingness to disagree with authority.

When people speak up to those higher in the organization—any organization—it helps stem illegal and unethical behavior, address mistreatment and injustice, and, more routinely, bring problems to the attention of those leaders who can authorize action. Employees of all types and levels confront problems and formulate ideas on the job; yet extensive social science research (including my own) shows that these employees, despite believing they have something useful to say, far too often choose silence over voice – most of the time, because they believe that speaking up is not “safe.”

 Of course, they rarely are talking about physical safety.  They’re talking about “psychological safety,” a work environment in which people feel free to voice concerns, ask for help and even admit mistakes.  When psychological safety is missing, people may worry about losing their job or being passed over for promotion if they speak up with an unpopular opinion, or they may worry about criticizing something that turns out to have been the “boss’s idea.”  Many of these fears are unfounded, but they persist. People instinctively recognize that, even if being fired for an unpopular view is rare, no one ever gets fired for silence.

General concerns about what others (especially higher-ups) will think is a major cause of this silence. With my colleague Professor Jim Detert at Cornell, I’ve studied employees in a wide range of organizations and discovered the existence of taken-for-granted beliefs about what, when and to whom to speak in hierarchical organizations. These beliefs, which we call implicit theories about voice, are widely held, self-protective and profoundly problematic for leaders and for organizations more generally.

Perhaps our most surprising finding was how often people believed that even speaking up with improvement ideas was risky. Think about it: Even positive, helpful thoughts seemed chancy to offer.  Although organizational research showed years ago that “bad news” travels poorly up the hierarchy, our research showed that people also systematically withhold the potentially “good news” of improvement ideas. This occurred even though people said they believed the organization needed input like theirs to remain successful in the future.

A widespread willingness to speak up about problems is critical to an organization’s ability to detect and prevent serious failures. In many organizations, any problem that can be hidden is hidden as long as possible. Soon after arriving at Ford, CEO Alan Mulally asked managers to color code their progress reports (green for good, yellow for caution, red for problems), according to Fortune magazine. He discovered that his first few staff meetings yielded nothing but green. Bluntly reminding managers that Ford had lost several billion dollars that year, Mulally called them on it, asking, “Isn’t there anything not going well?” After the first, tentative, yellow report came in with a serious problem and likely launch delay, Mulally responded to the deathly silence that followed with applause. After that, weekly staff meetings were full of color.

This widespread reluctance is why when leaders, including the president of the United States, are fortunate enough to identify a potential hire with a proven willingness to speak his or her mind, they should move quickly to welcome that person onto the team. It’s common sense – yet wildly uncommon practice – that strong leaders, good leaders, would want to hire people who disagree with them. Disagreement and dissent are crucial to good decision-making, and also to ethical corporate conduct. As Avis CEO Barry Rand put it a decade ago, “If you have a yes-man working for you, one of you is redundant.”