The unequal impact of parenthood in academia

INTRODUCTION

Several decades of research, across many fields, show that men typically publish more papers than women (1–3), but the reasons for and consequences of this difference remain uncertain. Explanations are numerous and include the hiring of women at lower-ranked and less-productive institutions (4–6), higher teaching and service loads (2, 7, 8), differences in research or task specialization (9, 10), more time invested in drafting initial results (11, 12), shorter career lengths (13), and the greater impact of childbearing and parenthood on women. Of these factors, parenthood affects a majority of faculty, both women and men, yet studies of its effect on scientific productivity are contradictory, finding negative (14–16), positive (17), or no relationship (11, 18, 19). During the COVID-19 pandemic, the impact of parenthood on researcher productivity has received much more attention, with early results indicating a relatively greater loss of productivity for women (20) and increase in domestic labor (21). Nonetheless, establishing the causal impact of parenthood on productivity has been difficult because studies often lack detailed information on career age, longitudinal productivity, the timing of parenthood, or changing social norms.

Parenthood can cause many changes to careers. For one, parenthood creates a new demand to allocate time to childcare and, for birth mothers, to recover from childbirth. In academia, women report more time spent on housework and childcare than men (22, 23). Among parents, while both men and women may decrease their work hours around parenthood, how they do can reflect gendered imbalances. Fathers often protect their research time, which is typically more important for career advancement, while mothers often protect their teaching (24). Hence, parenthood may decrease the available research time for women, more so than for men (16, 25). Parenthood may also change work preferences. For faculty who seek both parenthood and career advancement, having a child may drive them to become more productive and organized to achieve both (16, 25, 26). Parenthood may also shape the population of faculty through self-selection, because women are more likely to perceive academia as unwelcoming toward parents and thus seek careers outside academia (27–30).

Here, we quantify the productivity gap between early-career faculty who became parents and those who did not, and we directly measure parenthood’s differential effects on men and women. We leverage a survey from 2017 to 2018 of 3064 tenure-track faculty at 450 Ph.D.-granting computer science, history, and business departments across the United States and Canada that provides detailed information on faculty career age, the timing of parenthood, and research expectations (section SA). These three disciplines were chosen for their variation in gender representation and diversity in scholarly practices, which may correlate with the impact of parenthood (14, 31). The disciplines exhibit a relatively broad range of gender representation, with women representing just 15% of tenure-track faculty in computer science and 37% in history. The rates of collaboration and types of publications valued also vary across these fields. History faculty often write books and monographs with few, if any, coauthors, whereas computer science faculty publish in juried conference proceedings with many coauthors (section SB). These differences in scholarship and gender representation may influence the impact of parenthood on researcher productivity and provide our analysis some generality across field-specific characteristics.

In our analysis, we refer to faculty who self-identified as women and men and who had children by the time of our survey as mothers and fathers, respectively. We combine this survey with longitudinal data on 100,972 publications by these faculty and data on their institution-specific parental leave policies (sections SB and SC). Our study allows us to distinguish the impact of parenthood from known correlates of productivity, such as differences in career age (32), institutional prestige (33, 34), and changing publication rates over time (35), and to make within-gender comparisons, while accounting for factors that may differentially affect women or men in academic careers (e.g., higher service loads). In particular, we are interested in how gender roles and parenthood status, especially around the birth of their first child, intersect to shape academic careers.

Impact of parenthood on productivity

Across all three disciplines, among faculty who were at least 40 years old, a large majority (78.7%) reported having children, with lower rates among women compared to men (71.0 versus 82.2%, respectively; z = 6.00, P < 10−8). Men and women in our survey both become parents, on average, at the age of 33 years old (t = −1.04, P = 0.30). In contrast, the average ages of parenthood in the general U.S. population are 31 for men and 26 for women (36, 37), indicating that faculty, especially women, tend to delay their transition to parenthood (38). Consistent with this well-known trend in the general population toward reproducing later, we find that the age at which faculty become parents has also been increasing slowly (fig. S2). This age correlates only weakly with the prestige of the faculty member’s current institution (5), such that improving their institution’s rank by 100 corresponds to an additional delay of only 1 year (β = −0.01, t = −2.73, P = 0.01). Parents did not differ significantly from nonparents in the prestige of their appointments (Kolmogorov-Smirnov test, D =0.03, P = 0.59). Less than half (39.5%) of faculty became parents before starting their first faculty position, and mothers tend to have fewer children than fathers (averages of 1.8 versus 2.2; t = 7.17, P < 10−11).

If the productivity gap between men and women is entirely caused by gendered parenthood effects, then the productivity trends of men and women without children should be indistinguishable. To investigate this hypothesis, we examined each professor’s publication history and calculated their cumulative productivity over the 5 years before and 10 years after beginning their first assistant professor position. We find that the differences in cumulative time-adjusted productivity over this period (section SB) between men and women without children are 5.2, 0.8, and 1.5 papers over the 10 years on the tenure-track for computer science, business, and history faculty (insets of Fig. 1). That is, women without children produce on average 87.6 to 95.6% of the total number of papers than men without children produce. The residual (4.4 to 12.4%) remains unexplained by career age and parenthood and bears only on faculty like those we surveyed, i.e., tenure-track faculty at Ph.D.-granting departments.

Among parents from computer science, business, and history, mothers produced 13.1, 3.5, and 3.1 fewer papers (between 73.6 and 82.9%) compared to fathers over the same early-career period. This larger gap implies that gender differences associated with parenthood have a large effect on faculty productivity. If parenthood’s effect is gendered, then we would expect a productivity gap to emerge only after parenthood, not before, and its impact should be larger for mothers than for fathers. To isolate the effect of parenthood from gender, we used a comparative interrupted time series (CITS) analysis to directly compare the productivity of faculty with and without children around the event of parenthood. CITS has been used to study the impact of childbirth on men and women’s employment and wages (39, 40) but not previously to study academic careers. This comparison assigns counterfactual parenthood events to faculty without children, which we accomplish by drawing the timing of such an event from the empirical parenthood age distribution, stratified by parents’ gender, birth year, and field (section SD) (41). This procedure results in parents and counterfactual parents being statistically similar with respect to biological age, career age, and institutional prestige before their real or counterfactual event (table S6).

Before children, the annual productivity rates of men and women are similar, but even in this period of time, faculty of both genders who go on to have children are slightly more productive, on average, than those faculty who do not (t = 4.89 and t = 4.47, P < 0.01 for computer science and business and P > 0.1 for history; Fig. 2 and table S6). However, the annual productivity of mothers decreases immediately after childbirth, compared to nonmothers or men. The estimated CITS parameters indicate that the event of parenthood sharply decreases short-term productivity for mothers (−48.3 to −17.3%) but generally not for fathers with the exception of the field of history (t = 68.8, P < 0.01; section SD).

Although we cannot say whether collaboration causally affects this impact, we see that the magnitude of the effect is correlated with disciplinary rates of collaboration (table S4): The short-term impact of motherhood is greatest among history faculty, where there is less collaboration, and smallest among computer science, where there is more. Furthermore, because parenthood may drive individuals to leave academia before being observed by our sample—a selection effect that may be stronger for those individuals who experience larger parenthood productivity losses—these estimates are likely lower bounds of the true effect size.

Our results are inconclusive as to whether long-term publication rates are affected by parenthood. We also find no clear evidence that parenthood causes a short-term productivity increase for fathers, in contrast to previous suggestions that fathers may tend to use gender-neutral parental leave policies to increase their productivity relative to women (42).

Importance and usage of parental leave

Previous research indicates that early-career women often perceive academic careers as unfriendly to parenthood (27, 28), which contributes to women leaving academia at higher rates than men, a pattern sometimes called “the leaky pipeline” (13, 29, 30). Parental leave policies may help mitigate this effect by improving the recruitment and retention of parents, especially women. Consistent with prior work (43), women and men in our study used parental leave at different rates: Among leave-eligible parents, 91.8% of mothers but just 62.1% of fathers took parental leave at least once (z = 9.24, P < 10−19; Fig. 3D). Reflecting this gendered difference in behavior, nearly half of women (45.9%) indicated that parental leave policies were somewhat or very important in choosing their current faculty position, compared to 20.6% of men (χ2 = 141.81, P < 10−30; Fig. 3C). On the other hand, women and men placed similar and substantial value on the prestige of their current or a future position, rating prestige as somewhat or very important (89.9 or 56.9% of women and 89.3 or 57.6% of men; χ2 = 0.77, P = 0.68 and χ2 = 0.35, P = 0.84).

Among computer science faculty, early-career women with children reported less satisfaction with their current positions than women without children (58.3 versus 70.0%; t = −2.04, P = 0.05), suggesting parenthood as a potentially important factor in retention, although no such differences exist in the other fields we surveyed. Across all fields, 67.2 versus 72.7% of early-career women, with and without children, said that they were somewhat or very satisfied (t = −0.86, P = 0.39). Differences in job satisfaction remain insignificant when we compare men with and without children and older women with and without children. Among early-career men, 78.0% of those with children, versus 79.0% of those without children, indicated that they were satisfied at their current position. Among older women, overall job satisfaction was comparable among mothers and nonmothers (73.2 versus 72.2%). The availability of parental leave was not correlated with job satisfaction. Mothers at institutions that offered either more than or less than 10 weeks of parental leave indicated similar levels of satisfaction (72.1 versus 71.0%).

Parenting represents a threat to the ideal worker norm (44–46), an expectation of complete dedication to the workplace without responsibilities at home. While women and men are both subject to this expectation, women typically bear more childcare responsibilities than men (24) and thus are less likely to meet this ideal (45). To understand such norms, our survey asked respondents to estimate the likely and expected levels of productivity of others, as well as their personal productivity goals. Consistent with the belief that parenting violates the ideal worker norm, faculty estimate that mothers and fathers will likely publish fewer papers than faculty without children, and they expect decreases that are greater for women than for men (Table 1). Faculty also believe that women with children are likely to produce fewer papers than is expected of them (54.2% fewer of women and 37.2% of men, across all fields; χ2 = 77.75, P < 10−17; Table 1). To appear devoted to their work while being a parent, under an ideal worker norm, we might also expect fathers to aim for relatively high productivity. Despite faculty adjusting their expectations of parents’ productivity, we find little evidence that parenthood changes faculty’s expectations of their own productivity. Early-career faculty with children under the age of 10 reports similar publishing aspirations as those without children (Table 1). For example, in computer science, women with children aimed for 8.2 papers over a 2-year period versus 9.2 papers for those without children, and men with children aimed for 9.5 papers versus 8.5 papers for those without children (t = −0.95, P = 0.35 and t = 1.78, P = 0.08). These norms appear to be shaped by broad cultural forces, as the availability of generous parental leave policies, defined here as at least 10 weeks of paid leave, does not appear to affect faculty expectations of others’ productivity or their own productivity.

Trends in the impact of parenthood

The policy implications of these findings depend strongly on whether they will hold in the future. Longitudinal studies indicate a decade-long trend of fathers becoming more involved in parenting (47), leading to the hypothesis that the productivity gap studied here has been narrowing over time. We find evidence for increased parental involvement among men. For instance, of men who were eligible to take parental leave before the year 2000, only 38.7% took that leave, compared to 67.6% of those who first became eligible after (z = 4.64, P < 10−5). Despite this marked increase in the rate at which men are taking parental leave, their overall productivity has not decreased (Fig. 4). Concurrently, mothers increased their productivity, which shrank the productivity gap between mothers and fathers. Among faculty who had their first child before the year 2000, the 10-year cumulative productivity of women ranges from 61.4 to 82.0% of comparable men, whereas it rises to 75.7 to 110.0% for those who became parents after (Fig. 4). In parallel with the narrowing of this productivity gap, we note that there were concurrent increases in rates of collaboration (48), as well as the number of paid parental leave policies and gender-neutral tenure clock-stoppage policies (42, 49). However, as of 2018, only 42.9% of universities in our sample offered such policies (50).

Among institutions that offered any paid parental leave (63.6%), the average length of leave was 14.7 and 12.2 weeks for women and men, respectively, which is roughly equivalent to one academic term (Fig. 3A). A slight majority of policies (54.8%) did not clearly specify whether the leave applied only to teaching, teaching and service, teaching and research, etc. In our survey, most men and women express a preference for a parental leave policy that is gender neutral (48.1% of responses) with full relief for teaching and service (68.4%). However, ignorance of their institution’s current parental leave policy was not uncommon: 17.2% of early-career faculty with children reported not knowing whether their institution offered any parental leave benefits (Fig. 3B). This lack of knowledge about parental leave policies may suggest an overall lack of concern about those policies or the impact of parenthood on productivity. It may also reflect the often complex nature and convoluted language of these policies, which can include ad hoc negotiations with supervisors, leave-sharing requirements between parents, medical certifications, and more (51).