The geosciences suffer from a significant lack of diversity, particularly underrepresentation of women. Mentoring programs are recognized as a potential solution to improve recruitment and retention, but their effectiveness varies widely due to differences in program components. Existing research often examines benefits from role models or mentoring support in isolation, without distinguishing their unique contributions. Moreover, many successful mentoring programs are complex and costly, limiting their scalability and sustainability. This study addresses these limitations by conducting a randomized experiment to determine the critical elements of a successful mentoring program for undergraduate women in geoscience. The overarching goal is to identify the most effective combination of program elements that promote role modeling, mentoring experiences, and ultimately, persistence in geoscience careers. This will inform the design of more efficient and widely applicable mentoring initiatives.

Prior research highlights the persistent gender disparity in geosciences and the potential of mentoring and role modeling to address this. Several mentoring programs have been implemented to support women at various career stages, with evidence suggesting positive impacts on persistence. However, existing literature often focuses on either inspirational role models or tangible mentoring support, without isolating the unique effects of each. There's a lack of clarity on the optimal combination of program components to maximize impact, particularly concerning cost-effectiveness and scalability. This study aims to bridge this gap by empirically comparing different combinations of program elements to determine which are essential for success.

A randomized experiment was conducted with 158 undergraduate women from ten diverse universities. Participants were randomly assigned to one of three workshop groups: (1) Inspiration (exposure to female role models); (2) Inspiration & Inoculation (Inspiration plus training on mentorship and overcoming obstacles); and (3) Inspiration, Inoculation, & Introduction (all of the above plus introduction to a local female geoscientist mentor). Pre- and post-workshop surveys assessed various outcomes including the number of role models and mentors identified, quality of mentoring support, science identity, coping skills, and persistence intentions. A robust bootstrapped path analysis was employed to test the effects of workshop type on these outcomes, statistically controlling for pre-workshop levels. The analysis considered the role models and mentors as binary variables (0, 1, or multiple) to simplify analysis and focus on the key distinctions between the groups.

The results reveal significant differences across the three groups. The Inspiration group showed gains in identifying female role models, but not in mentor network size. The Inspiration, Inoculation, & Introduction group had significantly more mentors than the Inspiration group. Importantly, the quality of mentoring support did not differ significantly across groups. Path analysis revealed that having multiple mentors positively impacted science identity, active coping, and persistence intentions. Interestingly, identifying multiple female role models had a negative direct effect on science identity, but this was attributed to a statistical suppression effect due to the strong positive correlation between multiple role models and multiple mentors. The study highlights that the combination of Inspiration, Inoculation, and Introduction is crucial for fostering multiple mentoring relationships, which in turn positively influence motivation, coping skills, and persistence intentions. The indirect effect tests confirmed that the "Inspiration, Inoculation, & Introduction" group experienced significantly higher science identity, stronger coping skills, and greater persistence intentions due to having more mentors compared to the "Inspiration" group alone.

The findings provide valuable insights into the critical components of successful mentoring programs for women in geoscience. The study effectively distinguishes the unique benefits of role modeling from mentoring, showing that inspiration alone is insufficient. The combination of inspiration, inoculation, and introduction is necessary to build robust mentor networks, which are essential for promoting science identity, coping mechanisms, and ultimately, persistence. While science identity was the primary predictor of persistence in this model, future research should investigate the interplay between social support and sense of belonging. These findings challenge the common assumption that simply providing inspirational role models is sufficient to promote persistence in STEM. Instead, the data strongly suggests the need for proactive support and mentorship network development.

This study demonstrates that a multi-faceted approach combining inspiration, inoculation, and introduction is crucial for effective mentoring of undergraduate women in geoscience. The combination of these elements leads to a significant increase in mentor network size, ultimately promoting science identity, coping skills, and career persistence. Future research could explore the optimal strategies for mentor-mentee pairing, expanding the program to include men as mentors, and evaluating the impact on women with diverse intersecting minority identities to ensure inclusivity and broader applicability.

The study primarily focused on White and cisgender women, limiting the generalizability to women with other intersecting minority identities. The number of potential mentors was capped, potentially influencing the results. Future studies should explore the impact on a more diverse population and allow for unrestricted mentor identification.