The chief executive role is a tough one to fill. From 2000 to 2013, about a quarter of the CEO departures in the Fortune 500 were involuntary, according to the Conference Board. The fallout from these dismissals can be staggering: Forced turnover at the top costs shareholders an estimated $112 billion in lost market value annually, a 2014 PwC study of the world’s 2,500 largest companies showed. Those figures are discouraging for directors who have the hard task of anointing CEOs—and daunting to any leader aspiring to the C-suite. Clearly, many otherwise capable leaders and boards are getting something wrong. The question is, what?

In the more than two decades we’ve spent advising boards, investors, and chief executives themselves on CEO transitions, we have seen a fundamental disconnect between what boards think makes for an ideal CEO and what actually leads to high performance. That disconnect starts with an unrealistic yet pervasive stereotype, which is shaped in large part by the official bios of Fortune 500 leaders. It holds that a successful CEO is a charismatic six-foot-tall white man with a degree from a top university, who is a strategic visionary with a seemingly direct-to-the-top career path and the ability to make perfect decisions under pressure.

Yet we’ve been struck by how few of the successful leaders we’ve encountered fit this profile. That realization led us to embark on a 10-year study, the CEO Genome Project. Its goal is to identify the specific attributes that differentiate high-performing CEOs (whom we define as executives meeting or exceeding expectations in the role, according to interviews with board members and majority investors deeply familiar with the CEOs’ performance). Partnering with economists at the University of Chicago and Copenhagen Business School and with analysts at SAS Inc., we tapped into a database created by our leadership advisory firm, ghSmart, containing more than 17,000 assessments of C-suite executives, including 2,000 CEOs. The database has in-depth information on each leader’s career history, business results, and behavioral patterns. We sifted through that information, looking for what distinguished candidates who got hired as CEOs from those who didn’t, and those who excelled in the role from those who underperformed.

Our findings challenged many widely held assumptions. For example, our analysis revealed that while boards often gravitate toward charismatic extroverts, introverts are slightly more likely to surpass the expectations of their boards and investors. We were also surprised to learn that virtually all CEO candidates had made material mistakes in the past, and 45% of them had had at least one major career blowup that ended a job or was extremely costly to the business. Yet more than 78% of that subgroup of candidates ultimately won the top job. In addition, we found that educational pedigree (or lack thereof) in no way correlated to performance: Only 7% of the high-performing CEOs we studied had an undergraduate Ivy League education, and 8% of them didn’t graduate from college at all.

And when we compared the qualities that boards respond well to in candidate interviews with those that help leaders perform better, the overlap was vanishingly small. For example, high confidence more than doubles a candidate’s chances of being chosen as CEO but provides no advantage in performance on the job. In other words, what makes candidates look good to boards has little connection to what makes them succeed in the role.

But our most important discovery was that successful chief executives tend to demonstrate four specific behaviors that prove critical to their performance. We also found that when boards focus on those behaviors in their selection and development processes, they significantly increase their chances of hiring the right CEO. And our research and experience suggest that when leaders who aspire to the CEO’s office—87% of executives, according to a 2014 survey from Korn Ferry—deliberately develop those behaviors, they dramatically raise the odds that they’ll become high-performing chief executives.

The Four Behaviors

It’s rare for successful leaders to excel at all four behaviors. However, when we dug through our data, looking at the ratings our consultants had given candidates when evaluating them on fit for a CEO job and performance on 30 management competencies (for example, holding people accountable and the ability to motivate a team), we found an interesting connection. Roughly half the strong candidates (who had earned an A overall on a scale of A, B, or C) had distinguished themselves in more than one of the four essential behaviors, while only 5% of the weak candidates (who earned a B or C) had.

The behaviors we’re about to describe sound deceptively simple. But the key is to practice them with maniacal consistency, which our work reveals is a great challenge for many leaders.

[Here is the first of the four behaviors.]

1. Deciding with speed and conviction.

Legends about CEOs who always seem to know exactly how to steer their companies to wild success seem to abound in business. But we discovered that high-performing CEOs do not necessarily stand out for making great decisions all the time; rather, they stand out for being more decisive. They make decisions earlier, faster, and with greater conviction. They do so consistently—even amid ambiguity, with incomplete information, and in unfamiliar domains. In our data, people who were described as “decisive” were 12 times more likely to be high-performing CEOs.

Interestingly, the highest-IQ executives we coach, those who relish intellectual complexity, sometimes struggle the most with decisiveness. While the quality of their decisions is often good, because of their pursuit of the perfect answer, they can take too long to make choices or set clear priorities—and their teams pay a high price. These smart but slow decision makers become bottlenecks, and their teams either grow frustrated (which can lead to the attrition of valuable talent) or become overcautious themselves, stalling the entire enterprise. So it’s no surprise that when we looked more closely at the executives who were rated poor on decisiveness, we found that only 6% received low marks because they made decisions too quickly. The vast majority—94%—scored low because they decided too little, too late.

High-performing CEOs understand that a wrong decision is often better than no decision at all. As former Greyhound CEO Stephen Gorman, who led the bus operator through a turnaround, told us, “A bad decision was better than a lack of direction. Most decisions can be undone, but you have to learn to move with the right amount of speed.”

Decisive CEOs recognize that they can’t wait for perfect information. “Once I have 65% certainty around the answer, I have to make a call,” says Jerry Bowe, CEO of the private-label manufacturer Vi-Jon. But they do work actively to solicit multiple points of view and often poll a relatively small, carefully cultivated “kitchen cabinet” of trusted advisers who can be counted on for unvarnished opinions and sound judgment.

Bowe motivates himself to act on decisions by framing things this way: “I ask myself two questions: First, what’s the impact if I get it wrong? And second, how much will it hold other things up if I don’t move on this?” That approach, he says, also inspires his team members to trust their own judgment on operational decisions—which is critical to freeing the CEO up to home in on fewer but more important decisions.

To that end, successful CEOs also know when not to decide. Stephen Kaufman, former CEO of Arrow Electronics, suggests that it is all too easy to get caught up in a volley of decision making. He advises pausing briefly to consider whether a decision should actually be made lower down in the organization and if delaying it a week or a month would allow important information to emerge without causing irreparable harm.

But once a path is chosen, high-performing CEOs press ahead without wavering. Art Collins, former chairman and CEO of Medtronic, told us: “Employees and other key constituencies will quickly lose faith in leaders who waffle or backtrack once a decision is made.” And if decisions don’t turn out well? Our analysis suggests that while every CEO makes mistakes, most of them are not lethal. We found that among CEOs who were fired over issues related to decision making, only one-third lost their jobs because they’d made bad calls; the rest were ousted for being indecisive.