Editor's Note: The following research, created on behalf of Oliver Wyman's new Women in Healthcare Leadership Initiative, is from our Women in Healthcare Leadership 2019 report and executive summary, released at this year's StartUp Health Festival.

Healthcare is an industry where women make 80 percent of buying and usage decisions and 65 percent of the workforce. Yet, women are notably under-represented in industry leadership, making up approximately 30 percent of C-suite teams and 13 percent of CEOs. Unlike other industries, there isn’t a “women in healthcare” problem, but a “women in healthcare leadership” problem.

Our extensive interviews and research unearths the subtle, unintentional dynamics likely contributing to this gap. Our analysis presents a framework to activate organizational change to close the gender leadership gap and enable a more competitive, innovative industry.

Five New Things We Learned

1. The “hidden” factor in executive promotion.

Most C-suite leaders are unaware of how critical personal relationships are in the most senior leadership promotions. Trusting someone enough to promote them is influenced by 3 factors: ability, integrity, and affinity. When asked what factors into leadership promotions, most executives readily cite ability, and integrity, but not affinity. Yet after probing deeper, many recognized this less tangible, but influential factor is critical.

2. An uneven playing field.

Even if women are aware of the importance, there is a natural human tendency to form more effortless connections with “people like me” and men still hold most senior positions. On top of this, engrained perceptions of male-female relationships serve as impediments to developing deeper, empathetic work relationships.

3. An over-reliance on results.

Women view themselves as problem solvers at work and often becoming overdependent on results speaking for themselves. This belief only widens the “affinity gap” compared to men.

4. Misperceptions of ability.

Natural, unspoken differences in beliefs – like what makes a good leader – can often lead men and women to misinterpret each other’s behaviors and ultimately bias perceptions of ability. These misperceptions are exaggerated for women at the top as evaluation of traits like leadership or strategic thinking are more ambiguous and those evaluating candidates are more likely to be men.

5. The (lack of) a confidence gap.

While the confidence gap and imposter syndrome are frequently cited impediments for women, most of the senior women we spoke with did not lack confidence. Rather, they often spoke about having a different definition of what “prepared” means for a given role. Women play a different game than men and neither gender realizes it.