Closing Gender Gaps Through Workplace Diversity: The Intergenerational Effects of World War I

This paper asks whether exposure to greater female representation in the workplace can persistently reduce intergenerational gender gaps in labor market outcomes. The authors exploit the sudden, city-by-department variation in female employment within the U.S. federal government triggered by World War I mobilization. Using the Official Registers of the United States — biennial personnel rosters covering the near-universe of federal employees from 1913 to 1921 — linked to full-count decennial censuses (1900–1940), they construct a granular measure of each office’s (city × department) change in female share between 1915 and 1919, then trace labor force outcomes for the children of incumbent civil servants in the 1940 Census.

WWI caused the female share of the federal civilian workforce to jump by 13 percentage points — a doubling within two years (1917–1919). These wartime female entrants were younger, more likely to be single, more educated, more geographically mobile, and less likely to have been previously employed than their male counterparts, suggesting the war mobilized a previously untapped labor pool. The increase was driven almost entirely by clerical positions: the female share of the federal clerical workforce rose from roughly 30% to nearly 70% within two years.

The main finding is that a one standard deviation (SD) increase in parental exposure to female co-workers reduces the gender gap in labor force participation (LFP) among children of incumbent civil servants by 4.1–4.6 percentage points in the within-city, within-department specification — a decline in the mean gender LFP gap of approximately 8.6–9.6% by 1940. This effect is entirely driven by a higher propensity of daughters to work; sons’ LFP is unaffected. The intergenerational effect operates primarily through exposed fathers, including fathers without working wives, identifying a channel beyond the mother-to-daughter vertical transmission emphasized in prior literature. Children who were teenagers at the time of parental exposure show the largest effects, consistent with formative-years malleability. A placebo test using civil servants who left the same offices before the wartime shock shows no comparable effect, ruling out time-invariant office-level selection.

Parental exposure extends beyond the public sector: the private sector LFP effect is comparable in magnitude to the public sector effect. The gender earnings gap among children of exposed civil servants narrows by 12%, driven by daughters moving into higher-paying, previously male-dominated positions rather than by differences in hours or weeks worked. Marriage, fertility, and schooling differences only partially mediate the LFP effect, with a residual exposure effect remaining after controlling for these proximate determinants.

At the aggregate level, a 1 SD increase in city-level exposure to female federal workers raises overall female LFP by 0.9–1.0 percentage points, with no effect on male LFP, and the effect persists through 1940. A back-of-envelope calculation implies each additional female wartime civil service entrant generated approximately 2.4 additional women entering the workforce — a multiplier effect. Neighborhood-level analysis shows LFP gains are concentrated in enumeration districts where wartime female civil servants resided, and cities with greater female federal employment exposure also saw faster women’s club membership growth after WWI.

The scope conditions are important: the sample covers 70 cities and 8 federal departments with meaningful pre-war staffing; children must have been born by 1917; and the 1940 outcomes reflect adulthood labor decisions in a labor market shaped by subsequent decades of change. The design relies on within-city and within-department residual variation in female share change being conditionally exogenous, supported by lack of correlation with pre-war office characteristics.

Q: What was the scale of the WWI shock to female federal employment? A: The U.S. entry into WWI in April 1917 triggered a near-doubling of total federal civilian employment from roughly 150,000 to over 300,000 workers by 1919. Within this expansion, the share of female civil servants increased by 13 percentage points — a doubling of the female share within two years. The increase was driven almost entirely by clerical positions, where the female share rose from around 30% to nearly 70%.

Q: How do the authors measure parental exposure to female co-workers? A: Exposure is measured as the change in the share of female civil servants at the city-by-department (“office”) level between 1915 and 1919. The sample is restricted to offices with at least 20 civil servants in 1915 and cities with at least two federal departments, yielding 70 cities and 8 departments. The interquartile range of exposure across offices is approximately 10 percentage points, and cross-city and cross-department variation explains 58% of the overall variation, leaving substantial residual office-level variation for identification.

Q: What is the main intergenerational finding and its magnitude? A: A 1 SD increase in parental exposure to female co-workers increases the relative likelihood that a daughter works (compared to a son) by 2 percentage points in the baseline specification, and by 4.1–4.6 percentage points in the preferred within-city and within-department specification. Since daughters of civil servants are on average 48 percentage points less likely than sons to be in the labor force in 1940, this corresponds to closing the mean gender LFP gap by approximately 8.6–9.6%.

Q: Does the effect operate through daughters or sons? A: The effect is entirely driven by daughters. Parental exposure to female co-workers has no statistically discernible impact on the labor force participation of sons. The decline in the gender LFP gap is thus attributable to a higher propensity of daughters of exposed civil servants to work.

Q: What is the key placebo test, and what does it show? A: The authors exploit high-frequency personnel records to identify civil servants who selected into the same offices that would later be exposed but who left before the wartime shock occurred. These pre-departure leavers show no intergenerational exposure effects on their children’s LFP, ruling out the interpretation that time-invariant selection into particular offices drives the results.

Q: Which parent serves as the primary channel of transmission? A: Exposed fathers are the primary conduit. The effect for daughters is precise and sizable even when restricting the sample to fathers without working wives, suggesting the channel does not depend on children observing maternal employment. While the estimated effect through mothers is positive, it is imprecise — likely due to the small sample of female incumbent civil servants. This identifies fathers as a new channel of vertical intergenerational norm transmission, beyond the mother-to-daughter pathway emphasized in prior literature.

Q: How does children’s age at the time of parental exposure moderate the effect? A: The exposure effects are concentrated among children who were teenagers at the time of parental exposure during WWI. Children who were older and more likely to have already left the household or formed fixed beliefs show little to no detectable effect. This pattern is consistent with the formative-years hypothesis that experiences during adolescence shape lifetime economic behavior.

Q: Does the intergenerational effect extend beyond the public sector? A: Yes. The private sector LFP effect for daughters is comparable in magnitude to the public sector effect, with a 1 SD increase in parental exposure having approximately equal effects on LFP within public and private employment. There is also no measurable shift toward clerical occupations specifically, suggesting the channel is a broader change in attitudes toward women working, not transmission of information about specific government or clerical jobs.

Q: What is the effect on the gender earnings gap? A: A 1 SD increase in parental exposure to female co-workers closes the gender earnings gap among children of civil servants by 12%. This is not driven by differences in weeks or hours worked, but rather by daughters of exposed parents selecting into higher-paying and previously male-dominated occupations.

Q: How do the authors address the possibility that the results reflect local labor market conditions rather than parental exposure per se? A: By 1940, 67% of civil servant children lived in a city different from their parent’s WWI-era city. Even among children who moved to the same destination city — and thus face identical labor market conditions — variation in parental exposure at the origin city-by-department remains highly predictive of daughters’ LFP. Comparing children moving from the same origin city to the same destination city, those with parents in higher-exposure departments still show higher LFP, pointing to cultural transmission rather than local labor market demand.

Q: What do the marriage and fertility results indicate about mechanisms? A: Daughters of more exposed civil servants are less likely to be married (a 1 SD increase in parental exposure reduces the relative likelihood of daughters being married by 3.7 percentage points) and tend to have fewer children by 1940. A mediation exercise shows these observable differences in marriage, fertility, and education only partially explain the LFP increase; a statistically significant and economically large residual exposure effect remains, consistent with parental exposure shifting broader gender norms rather than only proximate determinants of labor supply.

Q: What does the spousal work decision evidence contribute? A: A 1 SD increase in male civil servants’ exposure to female co-workers increases the propensity of their subsequent wife to work by 0.5 percentage points after WWI. The effect is driven by marriages formed after the exposure and is not mechanically explained by men marrying their female co-workers. This revealed preference measure supports the interpretation that exposure changed men’s attitudes toward women’s work.

Q: What do naming patterns suggest about changing attitudes? A: Exposed parents are more likely to give daughters names that are less feminine — specifically, names with a lower share of vowels or less likely to end with a vowel — for daughters born after WWI. No comparable effect is observed for sons’ names. This provides supplementary evidence of a shift in paternal attitudes following workplace exposure to female co-workers.

Q: What are the aggregate city-level effects on female LFP? A: In a difference-in-differences design using cross-city variation in female federal worker exposure before and after WWI, a 1 SD increase in city-level exposure raises aggregate female LFP by 0.9–1.0 percentage points, with no effect on male LFP. The effect is persistent through 1940 and city-level exposure is uncorrelated with female LFP prior to WWI. A back-of-envelope calculation implies each additional female wartime entrant generated approximately 2.4 additional women entering the broader workforce — a social multiplier.

Q: Is there evidence of horizontal (non-family) transmission? A: Yes. The aggregate LFP gains are concentrated almost entirely in census enumeration districts where female wartime civil servants resided; neighboring districts without female entrants do not see comparable gains. Cities with greater increases in female federal employees also experienced faster growth in women’s club memberships, with this pattern appearing only after WWI and coinciding with the rise in female LFP. Both findings are consistent with social learning operating through residential proximity and community networks.

Q: How robust are the results to potential selection bias from imperfect census linking? A: The propensity of a civil servant’s child to be linked to the 1940 Census is — conditional on city and department fixed effects — uncorrelated with the parental exposure measure. The authors apply inverse probability weighting (IPW) to ensure the matched sample is balanced on baseline characteristics, and results remain virtually identical. Estimates are also stable across different linking strategies individually.

Q: What instrumental variable strategy is used and what does it find? A: The authors instrument for office-level female share change using the interaction of the 1915 clerical workforce share and an indicator for war-related departments — a pre-determined source of variation in the capacity and demand for female clerical workers. The IV estimates are consistent with the OLS main specification: parental exposure to female co-workers closes the children’s gender LFP gap.

Q: What is the policy implication regarding public sector hiring? A: The paper suggests that increasing gender representation within public sector employment can have labor market implications that extend well beyond the organization itself — across generations through vertical intergenerational transmission and across the broader community through horizontal social spillovers. The findings imply that public sector diversity policies can serve as a lever for broader, persistent reductions in gender gaps in the private labor market.

Office-level exposure: The city-by-department measure of the change in female share of civil servants between 1915 and 1919, capturing the granular intensity of each workplace unit’s contact with wartime female entrants; the interquartile range across offices is approximately 10 percentage points.

Intergenerational gender gap in LFP: The difference in labor force participation rates between daughters and sons of incumbent civil servants measured in 1940 adulthood, used as the primary outcome to capture whether parental workplace exposure transmits to children’s labor supply decisions.

Vertical transmission: The intergenerational channel through which exposed parents — identified here primarily as fathers, including those without working wives — convey changed attitudes or information about female work to their children, closing the gender LFP gap.

Horizontal transmission: The community-level channel through which the increased presence of female civil servants in a city spreads changed norms or information about women’s work to women who are not daughters of exposed co-workers, operating through residential proximity and social networks such as women’s clubs.

Social multiplier: The amplification of the direct effect of hiring female workers through behavioral spillovers; the authors’ back-of-envelope calculation estimates that each additional female wartime civil service entrant generated approximately 2.4 additional women entering the workforce.

Formative years: The period of adolescence during which children are argued to be most malleable in forming preferences and beliefs; exposure effects in this paper are concentrated among children who were teenagers at the time of parental exposure, with older children showing little effect.

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