Wharton’s Judd Kessler speaks with Wharton Business Daily on Sirius XM about his research on women and self-promotion.

The annual performance review is perhaps the most tedious and universally despised ritual of employment. These reviews typically include a self-evaluation in which employees must rate their own performance on a scale. It’s a subjective exercise that should ostensibly result in high marks all around, but new research from Wharton and Harvard finds otherwise: When it comes to self-promotion, women systematically rate themselves lower than men do, even when their work is objectively better.

The workplace divide along gender lines is nothing new. Women earning 85% of what men make for the same job is a common point of reference in the conversation around the wage gap. Even the recent Oscars drew attention for the lack of female directors among its nominees, a Hollywood reflection of the gender disparity that persists in real life. But the findings by Judd Kessler, Wharton professor of business economics and public policy, and Christine Exley, business administration professor at Harvard Business School, are worrisome because they indicate an inherent unfairness in how women may be perceived in the labor market. The tendency for women to undervalue themselves — whether in a formal performance review, a job interview, a staff meeting or a casual question about last week’s project — makes it more difficult to achieve parity and close the gender gap in the workplace.

“Our research suggests that hiring managers and employers should think twice before relying on subjective self-assessments to determine the performance of applicants or employees,” Kessler said. “The work also points to the potential benefits of relying on objective performance measures rather than self-assessments.”

In their study, “The Gender Gap in Self-Promotion,” the professors conducted a series of experiments to measure self-promotion. They recruited 1,500 Amazon Mechanical Turk workers to answer 20 math and science questions from the Armed Services Vocational Aptitude Battery (ASVAB), a multiple-choice entrance exam to join the U.S. military. Both genders performed roughly the same on the test, answering between 9 and 10 of the 20 questions correctly. Women slightly outdid the men, answering closer to 10 correctly on average, compared to closer to 9 on average for men.

First, Kessler and Exley measured the confidence of the participants by asking them to predict how many questions they answered correctly. Despite the actual results, men thought they answered more than 10 questions correctly, while women thought they answered fewer than 10 correctly.

“Our research suggests that hiring managers and employers should think twice before relying on subjective self-assessments to determine the performance of applicants or employees.” –Judd Kessler

Kessler and Exley then measured the participants’ self-promotion by asking them four subjective questions that might be on a performance review. That included rating their ASVAB performance on a scale of 1 to 100. Their answers revealed an even more dramatic difference, with men giving themselves an average score of 61, and women rating themselves at 45.

“So, it’s a 15-point difference for people who did basically the same,” Kessler said during an interview with the Wharton Business Daily show on Sirius XM. “If anything, the women did better. But women are saying, ‘We didn’t perform as well.’”

A ‘Persistent Gap’

The researchers created different versions of the study, including an incentivized version in which the participants were told that an employer will determine whether to hire them and what to pay them based solely on the participant’s response to a self-promotion question. Even when it was in their own best interest to aggrandize their performance, women did so less than men.

In another version, the participants were told ahead of time how they did on the test, yet women still rated themselves lower.

“What causes the persistent gap in self-promotion that we document is still an open question,” Kessler said. “Our experiment allows us to conclude that the gender gap in self-promotion is not driven by differences in confidence about performance between men and women, since the gender gap persists even after we tell subjects how well they did on the test and how their performance compares to others.”

One hypothesis is that socialization or gender-specific backlash could have led women to internalize the risks of self-promotion, he said. There is prior work that shows women are “punished” for self-promotion at work, which is often viewed negatively as bombast. This backlash may have socialized women to underplay their accomplishments, which could explain why they did so even in the experimental setting where gender was not disclosed to potential employers.

“What causes the persistent gap in self-promotion that we document is still an open question.” –Judd Kessler

In their study, Kessler and Exley note that they’re concerned about the self-promotion gender gap because it is pervasive in a wide variety of settings, from academia to the factory floor to corporate offices. “We focus our work on self-promotion because we view it as an understudied behavior that could have important implications for labor market outcomes,” the researchers write. “Among other contexts, individuals are often explicitly invited to engage in self-promotion: in applications to educational institutions, in job applications, in job interviews, and in performance reviews. Many additional environments provide implicit opportunities to engage in self-promotion (e.g., when casually discussing work or work related issues with colleagues or superiors, when discussing private contribution to group work, and when advocating for oneself in the workplace).

“The frequency of opportunities to engage in self-promotion means that it is has the potential to interact with other gender gaps that have been observed in the literature,” Kessler and Exley continue. More research is needed to understand how self-promotion impacts decisions like hiring and promotions, as well as how the gender gap in self-promotion can be mitigated, they add.

“We are eager to see whether there are interventions or policies that can close the gender gap in self-promotion,” Kessler said. “We would also love to better understand the underlying causes of the gap. If we have a better sense of what causes the gap, that may help us design solutions to mitigate it or — ideally — close it.”