The problem of the pay gap is that it is multifactorial : men being simply more assersive on average (which isn't far fetched) could explain it alone in some cases. The fact that more women tend to choose to be with their childdren is also definitely a factor. But a bia is probably at play too, bosses tend to be pretty old.
Bringing back some relevant studies I've posted before;
Women are socialised not to be assertive (especially with men, who are more likely to be in the positions they have to negotiate with), and when they are assertive they are penalised for it.
Sometimes it does hurt to ask.Four experiments show that gender differences in the propensity to initiate negotiations may be explained by differential treatment of men and women when they attempt to negotiate. In Experiments 1 and 2, participants evaluated written accounts of candidates who did or did not initiate negotiations for higher compensation. Evaluators penalized female candidates more than male candidates for initiating negotiations. In Experiment 3, participants evaluated videotapes of candidates who accepted compensation offers or initiated negotiations. Male evaluators penalized female candidates more than male candidates for initiating negotiations; female evaluators penalized all candidates for initiating negotiations. Perceptions of niceness and demandingness explained resistance to female negotiators. In Experiment 4, participants adopted the candidate’s perspective and assessed whether to initiate negotiations in same scenario used in Experiment 3. With male evaluators, women were less inclined than men to negotiate, and nervousness explained this effect. There was no gender difference when evaluator was female.
There have been clear measurements of measurable gender bias in hiring and treatment of women in various areas;
The Impact of Gender on the Review of the Curricula Vitae of Job Applicants and Tenure Candidates: A National Empirical StudyThe participants in this study were 238 male and female academic psychologists who listed a university address in the1997 Directory of the American Psychological Association. They were each sent one of four versions of a curriculum vitae (i.e., female job applicant, male job applicant, female tenure candidate, and male tenure candidate), along with a questionnaire and a self-addressed stamped envelope. All the curricula vitae actually came from a real-life scientist at two different stages in her career, but the names were changed to traditional male and female names. Although an exclusively between-groups design was used to avoid sparking gender conscious responding, the results indicate that the participants were clearly able to distinguish between the qualifications of the job applicants versus the tenure candidates, as evidenced by suggesting higher starting salaries, increased likelihood of offering the tenure candidates a job,granting them tenure, and greater respect for their teaching, research, and service records. Both men and women were more likely to vote to hire a male job applicant than a female job applicant with an identical record. Similarly, both sexes reported that the male job applicant had done adequate teaching,research, and service experience compared to the female job applicant with an identical record.
Science faculty’s subtle gender biases favor male studentsDespite efforts to recruit and retain more women, a stark gender disparity persists within academic science. Abundant research has demonstrated gender bias in many demographic groups, but has yet to experimentally investigate whether science faculty exhibit a bias against female students that could contribute to the gender disparity in academic science. In a randomized double-blind study (n = 127), science faculty from research-intensive universities rated the application materials of a student—who was randomly assigned either a male or female name—for a laboratory manager position. Faculty participants rated the male applicant as significantly more competent and hireable than the (identical) female applicant. These participants also selected a higher starting salary and offered more career mentoring to the male applicant. The gender of the faculty participants did not affect responses, such that female and male faculty were equally likely to exhibit bias against the female student. Mediation analyses indicated that the female student was less likely to be hired because she was viewed as less competent. We also assessed faculty participants’ preexisting subtle bias against women using a standard instrument and found that preexisting subtle bias against women played a moderating role, such that subtle bias against women was associated with less support for the female student, but was unrelated to reactions to the male student. These results suggest that interventions addressing faculty gender bias might advance the goal of increasing the participation of women in science.
Orchestrating Impartiality: The Impact of "Blind" Auditions on Female MusiciansA change in the audition procedures of symphony orchestras--adoption of "blind" auditions with a "screen" to conceal the candidate's identity from the jury--provides a test for sex-biased hiring. Using data from actual auditions, in an individual fixed-effects framework, we find that the screen increases the probability a woman will be advanced and hired. Although some of our estimates have large standard errors and there is one persistent effect in the opposite direction, the weight of the evidence suggests that the blind audition procedure fostered impartiality in hiring and increased the proportion women in symphony orchestras.
Do Masculine Names Help Female Lawyers Become Judges? Evidence from South CarolinaThis paper provides the first empirical test of the Portia Hypothesis: Females with masculine monikers are more successful in legal careers. Utilizing South Carolina microdata, we look for correlation between an individual's advancement to a judgeship and his/her name's masculinity, which we construct from the joint empirical distribution of names and gender in the state's entire population of registered voters. We find robust evidence that nominally masculine females are favored over other females. Hence, our results support the Portia Hypothesis.
Finally, a more sophisticated show of bias;
Performance-Support Bias and the Gender Pay Gap among StockbrokersOrganizational mechanisms, and their contexts, leading to gender inequality among stockbrokers in two large brokerages are analyzed. Inequality is the result of gender differences in sales, as both firms use performance-based pay, paying entirely by commissions. This paper develops and tests whether performance-support bias, whereby women receive inferior sales support and sales assignments, causes the commissions gap. Newly available data on the brokerages’ internal transfers of accounts among brokers allows measurement of performance-support bias. Gender differences in the quality and quantity of transferred accounts provide a way to measure gender differences in the assignment of sales opportunities and support. Sales generated from internally transferred accounts, controlling for the accounts’ sales histories, provide a “natural experiment” testing for gender differences in sales capacities. The evidence for performance-support bias is: (1) women are assigned inferior accounts; and (2) women produce sales equivalent to men when given accounts with equivalent prior sales histories.
That one is interesting; by measuring portfolio performance by past performance the women were doing just as well as the men, but they were assigned lower performing and less valuable portfolios.