Leadership was once called by historian James MacGregor Burns "one of the most observed and least understood phenomena on earth." Given the results of some recent research, this no longer appears to be the case.

Leadership development consultants Jack Zenger and Joseph Folkman published the results of a study they conducted on the skills that leaders need to succeed in their current positions. They asked more than 300,000 business leaders to rank the top four competencies from a list of 16 key leadership skills.

After working through the results, Zenger and Folkman came up with a ranking of the leadership skills that are most important for success. Here are the top 10.

1. Inspires and motivates others

Great leaders create a vision of the future that is vivid and compelling, and that motivates employees to want to achieve it. Everyone wants to work for a company that makes a difference in the world. As a leader, you are best able to help the members of your team connect what they do to the impact it has on customers and communities.

2. Displays high integrity and honesty

Great leaders are honest and transparent, and have high integrity--they do what they say they are going to do, and they walk their talk. As Umpqua Bank CEO Ray Davis said in his book Leading Through Uncertainty, "I always tell our people that they're entitled to get answers to every question they have. ... That doesn't mean they're going to like the answers. But it's going to be truthful, and I know they can deal with the truth. This might create additional questions, but we'll get through them. And we do."

3. Solves problems and analyzes issues

Ultimately, leaders are recruited, trained, and chosen to solve organizational problems, and to take advantage of opportunities in the marketplace. This requires not only excellent analytical abilities but also above-average people skills.

4. Drives for results

Some people are happy to sit back and watch the world go by, while others aren't unless they are making things happen in their organizations. Great leaders have a higher level of perseverance, stick-to-itiveness, and drive than most anyone else, and they can be counted on to get things done.

5. Communicates powerfully and prolifically

Great leaders communicate with their people often, and in a variety of ways. Whether it's by means of one-on-one conversations, team meetings, blog posts, email messages, phone or Skype calls, or any other medium, leaders don't talk about communicating--they just do it.

6. Builds relationships

Business is built on a solid foundation of relationships and trust. Without these two things, you can't have a business, or at least not a successful business. Take time every day to build relationships with the members of your team, your customers and vendors, your boss and your boss's boss, others in your industry, and your community. The stronger your relationships, the better a leader you will be.

7. Displays technical or professional expertise

Most leaders start out in business with a specific skill, such as selling or accounting or designing software. The best leaders build on their technical and professional skills over time, becoming valuable experts in their field and skilled at leading their team.

8. Displays a strategic perspective

Great leaders have a long-term vision of the future, and they avoid getting bogged down in the here and now. While they can be tactical when necessary, they maintain the strategic outlook necessary to guide their businesses to the best future possible.

9. Develops others

Just as they work to continuously develop and build their own technical and professional expertise, the best leaders set aside time (and money in their budgets) to develop their workforce. They look for the most promising employees, and provide them with the training they need to become their company's next generation of great leaders.

10. Innovates

According to General Electric's 2012 Global Innovation Barometer, which polled 2,800 senior executives on the state of innovation around the world, 92 percent of respondents agreed with the statement that "innovation is the main lever to create a more competitive economy." The ability to innovate is a key skill for every great leader.