New research proves gender bias extraordinarily prevalent in science, technology, engineering and math fields

"How Stereotypes Impair Women's Careers in Science," written by Ernesto Reuben, assistant professor of management at Columbia Business School, and recently published in Proceedings of the National Academy of Sciences, reveals the underlying biases of hiring managers, and also demonstrates the cost of discrimination.

"Studies that seek to answer why there are more men than women in STEM fields typically focus on women's interests and choices," said Professor Reuben. "This may be important, but our experiments show that another culprit of this phenomenon is that hiring managers possess an extraordinary level of gender bias when making decisions and filling positions, often times choosing the less qualified male over a superiorly qualified female."

In an experiment in which participants were hired to perform a mathematical task, both male and female managers were twice as likely to hire a man than a woman -- even when the managers had no information beyond a candidate's appearance and, therefore, gender.

Dr. Reuben continued: "The end result is not only a less diverse workforce and a male-dominated STEM field, but also a detriment to these companies for hiring the less-skilled person for the job."

The study is co-authored by the Kellogg School of Management's Paola Sapienza and the Booth School of Business's Luigi Zingales, was recently published in PNAS.

The Field Study

To test the biases of hiring managers, Reuben and his research partners designed an experiment in which about 150 participants, in the role of job candidates, would be hired to perform a math assignment: correctly summing as many sets of four two-digit numbers as possible over a period of four minutes. Previous studies have shown that this type of arithmetic task is performed equally well by men and women. All of the candidates completed the task and were given their scores. In some versions of the experiment, the candidates were allowed to tell the managers how well they had performed, while in others their test results were not revealed.

Close to 200 other subjects, in the role of hiring managers, decided whether to hire a particular candidate to perform the task. The hiring managers also completed computer-based behavioral testing that indicated the degree to which they held stereotypes about the performance of men and women in science and math.

The Results

The experiment, done on both female and male hiring managers showed that when the hiring manager had no other information other than a candidate's gender, they were twice as likely to hire a man than a woman, because they incorrectly believed that men are more talented in science and math, the researchers found. This bias often led to hiring the less-capable job seeker.

"In some situations up to ninety percent of the time when a mistake was made, it was made in favor of a man," Reuben says.

Even more surprising was when the candidates were allowed to tell the managers how well they will perform; women were still only half as likely to be hired as men, the study showed. Unlike men, women who indicated that they will score higher that their competitors were overlooked. With these mathematical test scores in hand, the researchers were able to prove a tangible cost to discrimination of hiring managers.

"If you're hiring someone who scores less on the test, more often than not you are hiring the less qualified candidate."

Further versions of the experiment demonstrated the difficulties of confronting negative stereotypes. When hiring managers were given information about the candidates' actual performance, the bias against women was reduced, but not eliminated, the researchers found.

"If you believe that women aren't good in math and science, you often resist updating that belief -- even when confronted by evidence to the contrary," Reuben says. "Raising awareness of this problem is a step in the right direction. Hiring managers need to disassociate themselves from general stereotypes and focus on the candidate. Leaving your personal experiences out of the process will likely land you the best candidate. Otherwise, you are hurting your company."