Eleanor J. Junkins1, Katharine M. N. Lee2, & Kathryn B. H. Clancy3,4 1 Department of Psychology, College of LAS, UIUC; 2 Division of Public Health Sciences, Washington University in St. Louis; 3 Department of Anthropology, UIUC; 4 Beckman Institute, UIUC Enhancing Knowledge through Engagement: Participation in an Unpaid Survey-Based Health Research Acknowledgments This research was supported in part by the University of Illinois Beckman Institute for Advanced Science and Technology, the University of Illinois Interdisciplinary Health Sciences Institute and the University of Illinois Center for Social & Behavioral Science Small Grant Program. Contact Me junkins2@illinois.edu References 1. Borno, H., Siegel, A., & Ryan, C. (2016). The problem of representativeness of clinical trial participants: Understanding the role of hidden costs. Journal of Health Services Research & Policy, 21(3), 145–146. 2. Kennedy-Martin, T., Curtis, S., Faries, D., Robinson, S., & Johnston, J. (2015). A literature review on the representativeness of randomized controlled trial samples and implications for the external validity of trial results. Trials, 16(1), 495. 3. Gobat, N. H., Gal, M., Butler, C. C., … & Nichol, A. (2018). Talking to the people that really matter about their participation in pandemic clinical research: A qualitative study in four European countries. Health Expectations, 21(1), 387–395. 4. Chin, L. J., Berenson, J. A., & Klitzman, R. L. (2016). Typologies of Altruistic and Financial Motivations for Research Participation: A Qualitative Study of MSM in HIV Vaccine Trials. Journal of Empirical Research on Human Research Ethics, 11(4), 299–310. 5. Sober, E. (1988). What Is Evolutionary Altruism? Canadian Journal of Philosophy Supplementary Volume, 14, 75–99. https://doi.org/10.1080/00455091.1988.10715945 6. Lee, K. M., Junkins, E. J., Fatima, U. A., Cox, M. L., & Clancy, K. B. (2021). Characterizing menstrual bleeding changes occurring after SARS-CoV-2 vaccination [Preprint]. Obstetrics and Gynecology. 7. R Core Team. (2022). R: A Language and Environment for Statistical Computing. R Foundation for Statistical Computing. 8. Silge, J., & Robinson, D. (2016). tidytext: Text Mining and Analysis Using Tidy Data Principles in R. JOSS, 1(3). 9. Hvitfeldt, E. (2020). textdata: Download and Load Various Text Datasets. 10. Grün, B., & Hornik, K. (2011). topicmodels: An R Package for Fitting Topic Models. Journal of Statistical Software, 40(13), 1–30 Conclusions It is evident that people found the survey through a variety of means and trusted sources. Many described googling for their symptoms and found our study. Altruistic motives, including existential, vernacular, and political, were apparent from this analysis. The implication of this work is that responsive, flexible post-clinical trial survey research with lower barriers of participation may be possible and may be able to reach people more widely. It may also serve to create active communication between scientists and the public to keep everyone informed of post-vaccine experiences. Future clinical trial research can be informed by attention to the large range of symptoms experienced by people. Aims 1) How did people hear about the study? 2) What were people’s interest in the study? 3) How do these interests relate to altruistic motivations of participation? Data Survey Instrument Demographics include age, country of birth, gender, race, and ethnicity. Open-ended text responses: • How did you hear about this project? • What is your interest in this project? Sample Data was derived from a large, online mixed-methods survey on menstruation and vaccine side-effects following COVID-19 vaccination6 (N~102,000). The current sample was limited to people in the USA who responded to both these questions in English. • N= 22,737 • Age M=33.7 years (SD=9.8) • 90.4% cisgender women; 83.4% white; 81.6% non- Hispanic Introduction Health research—and more specifically clinical trials for vaccines—is oft