A woman who studied nearly 200 self-made millionaires found they share one trait

After studying hundreds self-millionaires, leadership coach (and self-made millionaire) Dr. Jude Miller Burke found they tend to share one common trait in particular: conscientiousness.

"The personality trait most closely linked with high-level work achievement in the Millionaire Mystique study (and confirmed in other research) is conscientiousness, and millionaires and multimillionaires display it at a much higher level than less successful people, she writes in "The Millionaire Mystique," which is based on a three-year study of nearly 200 self-made millionaires.

Conscientious people tend to be super organized, self-disciplined, and dependable, Burke explains. They work hard in the face of challenges and can control their impulses.

They "reap rewards because they are the least likely to let their lives spin out of control when a crisis happens," Burke writes. "They plan carefully, execute their plans, and reap the self-esteem that comes from keeping their promises and working at a high level."

Burke is not the only one to recognize this commonality amongst wealthy, successful people. As Drake Baer wrote on Business Insider:

There's a staggering amount of research linking conscientiousness with success. A National Institute of Mental Health study found that conscientious men earn higher salaries. The National Institute on Aging also found that conscientiousness is linked to income and job satisfaction. Other studies show that conscientiousness is the most important factor for finding and retaining employment.

In addition to improving your own conscientiousness, you may want to start screening your dates for signs of conscientiousness: Having a conscientious spouse can boost your salary by $4,000 a year.

Another perk: Conscientious people stay healthier and live significantly longer.