Scholars at Indiana University  say that lower citation rates for women are due to bias.

In the past, fewer women worked outside the home and as that gradually shifted, there was hiring bias, which means historically women have had fewer science citations than men. That's simple numbers, just like fewer handicapped people and conservatives get citations in modern academia. But is that bias?

The authors say it is, and speculate it might be the trickle-down effects of having fewer female deans in science. 

Their cross-disciplinary quantitative analysis of academic publication patterns -  nearly 5.5 million research papers and over 27.3 million authorships - relating gender and research output found that female authors were underrepresented at a 30 percent to 70 percent authorship rate with males, and that for every female first author on a scientific paper there were nearly two (1.93) male first authors. They assigned gender using U.S. Social Security databases and other international records, and then aggregated the data by country, discipline and U.S. state.

Lead author gender and citation: papers with female authors in key positions are cited less than those with male authors in key positions, be they papers with one author, or those resulting from national or international collaborations. Numbers reflect average number of relative citations. Credit: Chaoqun Ni - Indiana University

They found that female authorship is more prevalent in countries with lower scientific output, that women's publication portfolios were more domestic than their male colleagues, and that articles with women in dominant author positions -- either first or last author -- received fewer citations than men in the same positions.

"Women profited less from the extra citations that international collaborations accrue," said co-author Cassidy Sugimoto. "And since citations play a central part in evaluating researchers, this situation can only worsen gender disparities."

Countries with the highest degrees of male dominance were Saudi Arabia, Iran, Japan, Jordan, the United Arab Emirates, Cameroon, Qatar and Uzbekistan.

U.S. states with the highest male dominance were New Mexico, Mississippi and Wyoming, while states and Canadian provinces with the greatest gender parity included Vermont, Rhode Island, Maine, Manitoba, Nova Scotia and Quebec.

"Note that some of these states and provinces that exhibited the most gender parity were also among the lowest ranking in terms of scientific output," Sugimoto said. Such was the case internationally: Female authorship was more prevalent in countries with lower scientific output, such as Macedonia, Sri Lanka, Latvia, Ukraine, and Bosnia and Herzegovina.

It is indisputable that age played a major role in explaining gender differences in scientific output, collaboration and impact, the team noted.

"Seniority, authorship position, collaboration and citation are highly interlinked variables, and the senior ranks of science bear the imprint of previous generations' barriers to the progression of women," Sugimoto said.

The report noted that since collaboration is one of the main drivers of research output and scientific impact, programs geared specifically toward fostering international collaboration for female researchers might be one way to advance parity.

"But we also recognize that if there was one simple solution the problem would already be solved," she added. "Behind the global imbalance are local and historical forces contributing to the systemic inequalities that hinder women's participation in the scientific workforce. Any realistic policy must take into account those social, cultural, economic and political contexts -- those micromechanisms -- that contribute to reproducing the past order."

Co-author Blaise Cronin, Professor of Information Science, said the research gives a glimpse of the current conditions, conditions which he predicted were on a trajectory toward change.

"Snapshots are starting points, not the whole story," he said. "The data may not lie, but I doubt that the world of science will be quite so blue 10 years from now."

"Global gender disparities in science" by Larivière, Ni, Goingras, Cronin and Sugimoto is published in Nature.