What the evidence says
The strongest causal evidence on this page comes from a single natural experiment far outside NLP or medicine: the adoption of blind (screened) auditions in symphony orchestras. Using variation in when orchestras adopted screens, Goldin (2000) finds that blind auditions increase a woman's probability of advancing from the preliminary round by 11 percentage points when no semifinal round follows, and increase her probability of winning the final round by 33 percentage points. These estimates come from a small subset of musicians who auditioned both with and without a screen (639 person-rounds for the preliminary estimate, 67 for the final-round estimate), and the paper notes some estimates carry large standard errors. At the level of overall hiring outcomes, blind auditions account for about one-third of the increase in the proportion of women among new hires, and about 25% of the increase in the proportion of orchestra musicians who are female — the latter figure from a less rigorous roster-based (associational) analysis rather than the audition fixed-effects model.
Outside that domain, a separate line of evidence looks at gender bias in machine translation. Cho (2019) finds that translation systems differ in how well they preserve gender-neutral pronouns: Google Translator scored 0.2992 versus Kakao Translator's 0.1184 on the same test corpus, and Naver Papago showed an unusual pattern of translating researcher and engineer into female pronouns more often than the other two systems, which the source describes as differing from expected social-prejudice patterns. Within the same system, formal Korean pronouns were translated with stronger male bias than informal pronouns, and occupation words showed more gender bias than sentiment or adjective words. Politeness of sentence structure showed no measured effect on translation gender bias.
A third, methodological line of evidence (Orgad 2022) does not measure gender bias in any real-world system directly; instead it measures how NLP researchers measure it. Most gender-bias studies in this literature use only intrinsic metrics, which the source states makes it difficult to determine what harm the underlying bias actually causes. Consistent with that gap, most papers measuring downstream (extrinsic) metrics measure three or fewer of them despite more being possible. This is a methodological-quality finding, not a bias-magnitude finding — it describes what the field measures, not how biased any given model is.
On medical students specifically, the evidence is thin and largely descriptive. One cross-sectional survey (anon 2025) reports that 64.35% of male medical students believed condoms reduce sexual pleasure, versus 87.85% of female students who expressed concern about oral contraceptive side effects — these are different outcome measures for each gender, not a comparison of the same belief across genders. The same source reports that gender differences in attitudes toward abortion "were evident," particularly regarding non-medical-context abortion and contraceptive-method perceptions, but supplies no quantification for that specific claim.
The topic name asks about gender-bias evaluation "in actual hi[ring]" — the orchestra-audition evidence is the only source here that measures a real hiring outcome rather than a translation output or a meta-level count of what researchers measure. No source on this page evaluates gender bias in hiring outside music performance, and no source connects the machine-translation or intrinsic/extrinsic-metric findings to any real-world harm or decision.
Where the evidence splits
Orgad (2022) reports that intrinsic and extrinsic bias metrics can move independently or even reverse relative to each other, but this is not a disagreement between two studies on the same quantity — it is one methodological source's own set of demonstrations (WEAT not correlating with extrinsic metrics per Goldfarb-Tarrant et al. 2021; a Pearson correlation for precision reversing sign between balanced and imbalanced test sets on the same model and dataset; compression's correlation with extrinsic metrics dropping from r²=0.567 to r²=0.025 across datasets). These are presented as evidence that intrinsic and extrinsic metrics measure different things, not as a contested empirical question with two camps.
Within the orchestra-audition evidence, blind auditions increase advancement in the preliminary round (+11 points) and the final round (+33 points), but have a negative effect on advancement from the semifinal round. Goldin (2000) calls this semifinal-round result "anomalous" and suggests it may reflect committees behaving more cautiously toward women once anonymity is removed, rather than straightforward bias — but the source itself frames this as an unresolved interpretive uncertainty, not a settled explanation. The magnitude of the semifinal-round effect is not specified.
Findings
Blind auditions increase women's probability of advancing in preliminary and final rounds, but decrease it in the semifinal round.
confidence — direction: high for preliminary/final rounds; high for semifinal roundconfidence — magnitude: medium for preliminary/final rounds; low for semifinal round (magnitude not specified)consensus: contested (within the same source) — semifinal-round result described as anomalous and unexplained
- mechanism
- concealing candidate identity (via screen) during audition removes visual/gender cues from evaluators
- effect
- +11 percentage points in preliminary-round advancement (when no semifinal follows); +33 percentage points in final-round win probability; negative (magnitude unspecified) in semifinal-round advancement
- conditions / moderators
- effect direction reverses specifically at the semifinal round; preliminary-round estimate drawn from 639 person-rounds, final-round estimate from 67 person-rounds; large standard errors noted for some estimates
Blind auditions increase the share of women among new hires and among orchestra musicians overall.
confidence — direction: mediumconfidence — magnitude: lowconsensus: thin, leaning toward the effect holding — single source, two different estimation approaches within it
- mechanism
- aggregation of round-level impartiality effects into hiring outcomes
- effect
- accounts for ~one-third of the increase in proportion female among new hires (audition fixed-effects estimate); accounts for ~25% of the increase in proportion female among orchestra musicians (roster-based estimate)
- conditions / moderators
- the one-third figure is an indirect calculation combining audition data with roster data under stated assumptions; the 25% figure uses roster data rather than the fixed-effects audition analysis
Machine translation systems vary in how much gender bias they exhibit, and bias varies by pronoun formality and content type within a system.
confidence — direction: highconfidence — magnitude: mediumconsensus: thin — single source, cross-sectional evaluation of three systems
- mechanism
- not established (source describes patterns, not the underlying model mechanism producing them, though it notes formal pronouns may correlate with male-dominated formal-writing training corpora)
- effect
- Google Translator gender-neutrality score 0.2992 vs. Kakao Translator 0.1184; formal pronouns show stronger male bias than informal pronouns; occupation words show more bias than sentiment/adjective words; politeness shows no measured effect; Naver Papago translated researcher/engineer into female pronouns more often than expected, unlike Google/Kakao
- conditions / moderators
- measured only for Korean-English translation using templated test sentences across three systems; not established whether patterns generalize to other language pairs or systems
Gender-bias evaluation studies in NLP predominantly measure intrinsic metrics and few extrinsic metrics, limiting inference about real-world harm.
confidence — direction: highconfidence — magnitude: high for the metric-count and correlation findings; medium for the "harm is hard to determine" inferenceconsensus: settled within this source that intrinsic and extrinsic metrics diverge; based on a single review of 36 papers
- mechanism
- intrinsic metrics (e.g., embedding-space measures like WEAT) do not correlate reliably with extrinsic (downstream task) metrics, and different dataset/metric combinations reveal different facets of bias, so measuring only one narrow slice does not establish downstream harm
- effect
- most reviewed studies use only intrinsic metrics; most papers that do measure extrinsic metrics measure three or fewer; WEAT does not correlate with extrinsic metrics (Goldfarb-Tarrant et al. 2021); a precision correlation reverses sign (positive to negative) between imbalanced and balanced test sets on the same model; compression's correlation with extrinsic metrics drops from r²=0.567 to r²=0.025 across datasets
- conditions / moderators
- these are methodological/measurement findings about the research literature itself, not measurements of bias magnitude in any deployed system
Medical students show gender differences in health-related beliefs and attitudes, including toward contraception and abortion.
confidence — direction: high for the condom/contraceptive-belief figures; medium for the abortion-attitude claim (no quantification)confidence — magnitude: high for the condom/contraceptive figures; low for the abortion-attitude claimconsensus: thin — single cross-sectional source
- mechanism
- not established
- effect
- 64.35% of male students believed condoms reduce sexual pleasure vs. 87.85% of female students who expressed concern about oral contraceptive side effects (different outcome measures per gender, not a shared metric); gender differences in abortion attitudes described as "evident," particularly for non-medical-context abortion and contraceptive-method perceptions, with no quantification given
- conditions / moderators
- cross-sectional survey of medical students; not established whether findings generalize beyond the surveyed population