The study addresses the persistent inequities in STEM education, particularly for historically marginalized communities (HMC) including women, Black, Latinx/a/o, Indigenous peoples, individuals with disabilities, and those affected by poverty. The researchers highlight the importance of STEM literacy for addressing global challenges and emphasize that informal STEM learning experiences can play a crucial role in bridging the opportunity gap. The Institute for Systems Biology's (ISB) Systems Education Experiences (SEE) program, established in 2003, serves as the case study. Initially a 320-hour summer internship, SEE expanded to include four additional models (Ambassadorships, 90-hour courses, 40+ hour workgroups, and 22-hour short courses) over five years, dramatically increasing participation. This expansion provides a unique opportunity to investigate the impact of different program durations and formats on STEM learning outcomes, especially for students from HMC. The study aims to determine the progress made by HMC students in STEM pathways, identify successes and challenges in their engagement with authentic STEM experiences, and pinpoint aspects of informal STEM learning experiences that support their progress. The findings are expected to offer valuable insights for researchers and informal science educators to promote equitable STEM learning.

The study draws upon several theoretical frameworks and research findings to inform its approach. It incorporates sociocultural theories of learning, emphasizing the transformation of participation within communities of practice. The authors acknowledge the social and material construction of learning settings that may privilege certain groups, and they discuss how SEE's program design principles aim to counteract this bias. The study emphasizes the importance of broadening participation through consequential participation, enabling students to engage in authentic STEM practices, develop science-linked identities, and connect science to their everyday lives and communities. Key concepts include Schreiner's (2010) concept of thriving, the Equity-Oriented Conceptual Framework for K-12 STEM Literacy (Jackson et al., 2021), and the role of informal settings in the STEM learning ecosystem. The study focuses on six overlapping STEM equity constructs: engagement, awareness and intent (within STEM pathway progression), identity, social capital, and 21st-century learning skills. Each construct is defined and contextualized with a review of relevant literature.

The study used a mixed-methods approach, analyzing data from 239 high school students who participated in SEE programs between 2003 and 2021. Data collection involved retrospective surveys and interviews. Alumni (56 participants from 2003-2019) completed a retrospective survey assessing the impact of SEE on their STEM pathways, comparing their experiences to high school and other extracurricular activities. A four-point Likert scale was used to rate the extent to which SEE supported progress in various aspects of the thriving framework. A separate survey was administered to 183 students from the 2019-2021 cohorts (320-h internship, 90-h course, 40+h workgroup, 22-h short courses), employing both pre- and post-experience assessments using validated tools and Likert scales to measure the six chosen constructs. Open-ended questions allowed students to identify specific aspects of the programs that influenced their responses. Statistical analysis (two-sided t-tests) was performed to evaluate significant differences. Qualitative data from open-ended survey responses were coded to identify emergent themes. Data was analyzed to ascertain whether program duration or format (in-person vs remote) significantly impacted outcomes for HMC students. The study explicitly acknowledges potential response bias due to the survey being sent by SEE staff. Measures to mitigate bias included careful survey design and framing.

The study's key findings indicate that SEE experiences positively impacted students' STEM pathways regardless of program duration (320-h, 90-h, 40+h, 22-h). Alumni reported significantly higher ratings for SEE's contribution to their course of study, career pathways, STEM content and practices, and societal connections to STEM compared to high school and other extracurricular activities. Across all SEE experiences, students demonstrated substantial gains in engagement (satisfaction and interest), awareness of STEM careers, STEM identity, intent to pursue STEM careers, social capital, and 21st-century learning skills. While longer programs generally showed greater percentage changes, shorter programs still yielded significant positive impacts. The analysis of the 320-hour internship program showed that the mode of delivery (in-person vs. remote) did not significantly impact overall outcomes; however, the remote format presented some logistical challenges for the 22-hour program. Qualitative data revealed that interactions with STEM professionals, authentic research experiences, and use of professional tools and materials were key factors contributing to the positive outcomes. The 22-hour program showed some limitations in adequately supporting career awareness and social capital development, potentially due to limited time for such activities. Students' explicit connection to program goals was important. Overall, 80% of student participants were from HMC.

The study's findings strongly support the effectiveness of informal STEM learning programs, like SEE, in promoting equitable STEM education for HMC students. The consistent positive impacts across diverse program formats highlight the robustness of SEE's design principles. The findings counter the traditional focus on graduation rates as the sole measure of success in STEM, providing a more comprehensive view of STEM pathway progression emphasizing 'thriving'. The importance of authentic research experiences, interaction with diverse STEM professionals, and a supportive community are highlighted. The study also acknowledges limitations, particularly in short-duration programs, where limited time may compromise in-depth career exploration and social capital development. These limitations point to the need for thoughtful program design that balances content delivery with career awareness and community-building activities. The study's findings contribute significantly to the field of informal STEM education by providing practical recommendations for designing and implementing effective and equitable programs.

This research demonstrates the effectiveness of informal STEM learning experiences in fostering STEM engagement and success for students from historically marginalized communities. The study's key contributions are: showcasing the impact of SEE on diverse program formats, highlighting the importance of authentic research and professional interactions, and suggesting strategies for enhancing program design. Future research could focus on longitudinal studies tracking long-term career paths of SEE participants, investigating the impact of specific program components on different HMC subgroups, and exploring new program models to reach a wider range of students. This research underscores the need for increased investment and support for informal STEM education initiatives committed to equity and inclusion.

While the study employs a mixed-methods approach and addresses potential response bias, several limitations should be considered. The retrospective nature of the alumni survey might introduce recall bias. The sample sizes for some cohorts were relatively small, potentially limiting the generalizability of findings. The self-reported nature of the data requires caution in interpreting results. Although efforts were made to mitigate bias, the fact that the survey was sent by SEE staff may still have influenced responses. The study focused solely on one program's experiences, which limits generalizability to other programs. Further research is needed to confirm these findings with broader samples and diverse programs.