Female leaders are no longer viewed as inferior to their male counterparts, new research revealed.

When it comes to being perceived as effective leaders, women are rated as highly as men, and sometimes higher, according to a meta-analysis published by the American Psychological Association.

"When all leadership contexts are considered, men and women do not differ in perceived leadership effectiveness," said lead researcher Samantha Paustian-Underdahl, of Florida International University. "As more women have entered into and succeeded in leadership positions, it is likely that people's stereotypes associating leadership with masculinity have been dissolving slowly over time."

The research discovered that while men tend to rate themselves as significantly more successful leaders than women rate themselves, when ratings by others were examined, women came out ahead on perceptions of effectiveness.

As part of the study, Paustian-Underdahl and her colleagues expanded on "role congruity theory," which hypothesizes that there is greater prejudice toward women as leaders because the stereotypical woman isn't seen as possessing leadership qualities.

"Women are typically described and expected to be more communal, relations-oriented and nurturing than men, whereas men are believed and expected to be more agentic, assertive and independent than women," the study's authors wrote.

The researchers expanded on the theory by applying it to both men and women, arguing that as organizations have become fast-paced, globalized environments, some organizational scholars have proposed that a more feminine style of leadership is needed to emphasize the participative and open communication needed for success.

For their analysis, researchers analyzed 99 data sets from 58 journal publications, 30 unpublished dissertations or theses, five books and six other sources, such as white papers and unpublished data. Sample sizes ranged from 10 to 60,470 leaders in both the U.S. and Canada.

When looking only at ratings submitted by others -- as opposed to self-ratings – researchers found that women were seen as more effective leaders than men in middle management, business and education organizations. Additionally, women were seen as more effective when they held senior-level management positions.

The researchers theorize that some of this effect could be due to a "double standard of competence," meaning some people presume that women leaders have to be extra competent to get into top positions.

"These findings are surprising given that men on average continue to be paid more and advance into higher managerial levels than women," Paustian-Underdahl said. "Future research needs to examine why women are seen as equally (or more) effective leaders than men, yet are not being rewarded in the same ways."

The study was co-authored by Lisa Slattery Walker and David Woehr of the University of North Carolina at Charlotte.