By Published: Oct. 26, 2021

Members of the United States' 11th Congress are sworn in at the Capitol

Members of the 117th Congress of the United States are sworn in at the Capitol in January 2021. Currently, 119 women hold seats听in the U.S. House of Representatives, a record number. (Credit:听Franmarie Metzler)

When women gain power in national legislatures such as the U.S. Senate or Israeli Knesset, countries begin to spend more on priorities like education and health care.听

That鈥檚 the conclusion of new research led by CU听Boulder and in the journal Political Science Research and Methods.听

The study comes as women are winning more seats in parliaments and national assemblies around the globe, but still struggling to gain a majority in many countries.

In Rwanda, for instance, women fill 56%, or 59 out of 106, of the seats in the nation鈥檚 parliament鈥攖he largest representation of women in any national legislative body in the world. Lebanon, Sri Lanka and Nigeria, meanwhile, join a host of countries where the representation of women languishes in the single digits. The United States falls in the middle with women holding 27%, or 143 out of 535, House and Senate seats.听

鈥淭he big question this paper asks is: Does increasing the representation of women in politics actually have a meaningful effect on legislation?鈥 said Hannah Paul, co-author of the new study and PhD candidate in political science at 兔子先生传媒文化作品.

Attendees at an event in Kigali, Rwanda, in 2017 called the 3rd Womens League Congress, which was organized by the country's RPF鈥揑nkotanyi political party

Attendees at the RPF-Inkotanyi 3rd Women's League Congress in Kigali, Rwanda, in 2017. The RPF-Inkotanyi is the political party of Rwandan President Paul Kagame. (Credit: via )

To find out, she and her colleagues used machine learning tools to sift through real-world data from nearly 150 nations. They discovered that women鈥檚 representation matters, but it鈥檚 complicated.

Take education.听Based on the team鈥檚 calculations, increasing numbers of women in national legislatures can spur a bump in spending on education, but only once they reach about 20% representation. When women occupy more than 40% of seats, however, education spending tends to plateau.

The findings highlight just how complex the relationship between gender and politics can be, said study coauthor Andrew Philips, assistant professor of political science.

鈥淲hen the representation of women is low, politicians tend to treat them like window dressing: They鈥檙e there to make the party look good,鈥 he said. 鈥淎t the same time, you can get to a point where there are so many women in politics that they can now prioritize different issues than they did before.鈥

Critical mass

The study is the latest to tackle a sticky topic in the field of political science: critical mass theory. The idea, Philips explained, emerged out of research into the role of women in the business world. Say you鈥檙e dealing with a company鈥檚 board. If only one or two women sit on a board of 15 people, they might not be able to enact too many changes. Critical mass theory, however, posits that if women leaders hit a minimum threshold for power鈥攕ay they now hold five out of 15 seats鈥攖heir influence will increase dramatically.听

The problem is that research on the impact of critical mass has been mixed, Paul said.

鈥淭his idea has been debated for decades,鈥 she said. 鈥淲hat we鈥檙e trying to do is adjudicate whether we should keep this theory around. Or maybe these relationships are more nuanced.鈥

The researchers, including Kendall Funk from Arizona State University, scanned thousands of data points to get at that question鈥攏ot only looking at information on nations鈥 expenditures but also controlling for potentially confounding factors like unemployment, level of democracy and female life expectancy. Previous studies of city mayors and other politicians have shown that , while men lean into security and transportation.

Sweet spot

The approach panned out. The team discovered that a sweet spot seems to exist where women can affect the most change in the fastest amount of time.听

When women occupy roughly 15% to 35% of a country鈥檚 legislature, spending on health care jumps up sharply from about 6.4% of GDP to more than 6.7%. Beyond that point, however, adding more women to a parliament, assembly or congress no longer moves the spending needle much. At the same time, defense spending plummets as more women join legislatures, leveling off at about 1.8% of GDP, when women reach 35% representation.听

鈥淭here鈥檚 this interval of time in which women are shaping how government spends money on education and health care,鈥 Paul said.

Moving forward, the researchers hope to dig even deeper into their data to probe what kinds of impacts these changes might have. Does the presence of women in national legislatures lead to an increase in education levels or the life expectancy of citizens? For now, they said that the results point to one big conclusion.听

鈥淭he quick takeaway here is that critical mass theory is not dead,鈥 Philips said.