Despite being one of the most ethnically diverse countries in the study's sample, Liberia has seen GDP grow sharply under President Ellen Johnson Sirleaf, the first democratically elected female head of state in Africa. (Lucas Jackson / Reuters)

Plenty of research has looked at what impact typically feminine leadership traits—collaborative,  inclusive, consensus-driven—can have in the boardroom. But what about in elected office?

Professors Susan Perkins of Northwestern University and Katherine Phillips of Columbia (who was a colleague of Perkins' at Northwestern when they conducted the study), along with doctoral student Nicholas Pearce, set out to look at that question. In a recent paper published in the Fall/Winter issue of Columbia's Journal of International Affairs, they explored the relationship between GDP growth and female presidents and prime ministers over the past 50 years, however few there may be.

They found that, while there's no difference in economic growth recorded under male and female leaders in general, there is a correlation between female leaders and higher GDP growth in countries that have a lot of ethnic strife. The takeaway? In places where there is more ethnic infighting, the qualities female leaders tend to showcase—or at least the symbol of empowerment they send to other marginalized groups—could be a factor in helping to quell some of that conflict, leading to more stability and faster-growing economies.

I recently asked Phillips to elaborate on her research. Our conversation has been edited lightly for length and clarity.

Q. Tell us what you were looking to find when you embarked on this study.

A. We were interested in some findings in the political science and economics arena on the impact of what's called "ethnic fractionalization." The research has shown pretty robustly that the more diverse the country is, the smaller the GDP growth over time.

We were initially interested in leaders who were part of an ethnic group, and their impact on GDP. But it was really hard to find reliable data on the ethnic background of leaders. We were also collecting data on gender, and women are often perceived as lower-status individuals in the world. Perhaps, we thought, our hypothesis might apply to women leaders at the top.

Q. What is "ethnic fractionalization," and how does it relate to GDP?

A. Basically, it's a measure of the likelihood that you will interact with someone of a different ethnic group. It's a probability measure based on the distribution of different ethnic groups in a country. If a country is completely homogeneous, the measure is zero. Where there's a lot of diversity, it's one. The MIT researchers who studied this found that if you correlate that to economic growth (there's no causal relationship here), it's negative.

Q. In other words, high levels of ethnic diversity and conflict are tied to lower economic growth? I thought diversity was a good thing. 

A. Yes, but ethnic diversity is different at the country level. In corporate boardrooms, people aren’t trying to kill each other. They aren’t trying to grab more resources. More ethnic diversity adds governing complexity at the country level because of conflicts of interest between groups, and that can undermine economic growth.

Q. What did your research show?

A. If you look at the data and just look at the relationship between having a male or female leader and the amount of GDP growth, there’s no effect. But if you take the country's measure of ethnic fractionalization into consideration, that’s when you see a difference. The negative impact of diversity is minimized when you have a female leader. In fact, it sometimes turns positive.

We can't say that one causes the other. It could be that only those countries that already have high ethnic diversity are selecting women, or that they're putting them into place only after GDP is already on the uptick. That seems less plausible, though, because women tend to be put into more precarious leadership positions rather than more stable ones.

Another possible explanation is that a woman is put in when things are really, really bad, and the improvement in economic growth is only a return to the mean. Then what about when a man gets put into a really, really bad situation? That doesn't explain the finding either.

I think part of what’s occurring is that when these places have a lot of turmoil, and when women are put into leadership positions, it immediately sends the signal that there’s going to be change. It could be the behavior of people around her. She symbolizes collaboration, she symbolizes change. Maybe, they think, this is an opportunity to change the way we’ve been operating—to have a more collaborative, inclusive effort to push the entire country forward.

Q. Many people, surely, will find it surprising that there have been enough women leading countries to have a representative sample. How many women leaders did you look at in your study?

The numbers are small. We have data over 55 years. When you look at the number of "leader years," or the total combined number of years each leader served, only 2.22 percent of them were held by a female leader at the national level. And that’s with queens included, not just female presidents or prime ministers. Over the 50-plus years, there have been 48 female presidents and prime ministers across 139 nations. We left out the queens because historically they have not had governing power.

Do we have reliable analyses and reliable predictions in terms of what is required to make valid claims? Yes. Would we like to have more? Absolutely. We should be cautious about what we’re trying to interpret, but the pattern of data shows that in countries that have high ethnic diversity, there is a difference in how much GDP growth exists when there’s a man versus a woman in charge.

It's also consistent with a lot of other research we see about female leaders, their leadership style and how they deal with conflict. We know, for instance, that women tend to be less focused on social dominance. That's relevant to what happens when ethnic diversity is high. We also know from other research that when people see a female leader, they associate her with change. When things are more competitive within the group, people think women might be more able to deal with that. You triangulate the data with other things you know and with the theories that exist. We’re confident that this is worth really talking a closer look at. There's certainly a pattern that’s emerging from this data, even with the small numbers.

Q. Where does the United States fall in terms of the ethnic diversity measure? And what does this mean, say, when there is a possibility Hillary Clinton will be the Democratic nominee in a few years? 

Our country is about in the middle of the ethnic fractionalization measure. It's not really diverse, and it's not really homogeneous, so it's really hard to know [what kind of impact a female leader might have]. There are a lot of conversations going on around gender that give Hillary more momentum than she may have had in the past.

But one of the things we know is women tend to be put into what people would call precarious leadership positions. There's a term for it: the "glass cliff." To the extent that this country is perceived as really needing change and being in a position that’s not so great, people might be more inclined to vote for a woman. 

Jena McGregor is a columnist for On Leadership.

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