Here is an excerpt from an article written by Jane Edison Stevenson and Evelyn Orr forHarvard Business Review and the HBR Blog Network. To read the complete article, check out the wealth of free resources, obtain subscription information, and receive HBR email alerts, please click here.

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Only 6.4% of Fortune 500 companies are run by female CEOs, and while there is incremental progress — there are 32 female CEOs this year, the highest percentage ever, compared with only 21 last year — the rate of change can feel excruciatingly slow.

But what if there were a way to make breakthrough progress by applying research-based tools and strategies to boost these numbers faster? With that objective in mind — and as part of their 100×25 initiative, which is pushing for female CEOs to lead 100 of the Fortune 500 by 2025 — the Rockefeller Foundation provided a grant for Korn Ferry to design and execute a research project geared to developing action-oriented initiatives to create a sustainable pipeline of female CEOs.

We secured the participation of 57 female CEOs — 41 from Fortune 1000 companies and 16 from large privately held companies. We then conducted a series of in-depth individual interviews, delving into pivotal experiences in their personal history and career progression, and using Korn Ferry’s executive online assessment to measure key personality traits and drivers that had an impact. Our goal: to crack the code of these women’s success, in order to help organizations better identify and leverage their highest-potential female leaders and to ensure more women succeed in the future.

Throughout the research, Korn Ferry used our best-in-class CEO benchmark, which comprises typical scores for CEOs (virtually all male) who are in the 99th percentile of work engagement, as a touchstone to highlight similarities and underscore differences for the women in the study.

Following are six insights that emerged from the study, with illustrative quotes from some of the CEOs we interviewed — unattributed to ensure complete candor — that are directly relevant to building a pipeline of female CEOs.

[Here are the first two insights.]

Women could be ready for the CEO role sooner. Prior to landing the top job, female CEOs in the study worked in a slightly higher number of roles, functions, companies, and industries than men leading companies of a comparable size. In essence, the women worked harder and longer to get to the same place. They were four years older, when compared with benchmark data, before becoming CEO and brought more-diverse functional and industry experience to the position. Some women expressed frustration about the delay. As one put it, “There are still too many women in support functions. They have to prove themselves 10 times over before they’re actually given the opportunity, so their development takes longer.” With women apparently expending more energy to achieve the same result, the longer runway gives them fewer years to have an impact in the top job.

Women are driven by achieving business results and making a positive impact. Drive in high-achieving women manifests differently from the top-performing, predominantly male CEO benchmark group, despite their capabilities showing as almost identical on other fronts. While female CEOs were comparably motivated by collaborating with other people, taking on more responsibility, power, and scope, the interviews strongly suggest that status, power, and reward were not enough to attract women to the role. Ambitious women may be hesitant to self-promote, driven more by a sense of purpose and a desire to contribute value and shape culture. More than two-thirds of the CEOs we assessed said they were motivated by a sense of purpose and believed that the company could have a positive impact on its community, its employees, or the world around them. Nearly one-quarter said creating a positive culture was one of their most important accomplishments. One woman echoed the sentiment we heard throughout our interviews: “Sure, the shareholders made a lot of money and we hit all our targets. But what else did you do? What did you do for your communities and for your people?”

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Here is a direct link to the complete article.

Jane Edison Stevenson is Global Leader for CEO Succession and Vice Chairman Board & CEO Services, Korn Ferry.

Evelyn Orr is Vice President and Chief Operating Officer, Korn Ferry Institute.