University of Wisconsin–Madison

Statistics major Yalei Zhao wins prestigious undergraduate thesis award

Yalei Zhao, winner of the Trewartha Senior Honors Thesis Research Award

Yalei Zhao x’25, a Statistics and Mathematics double major at UW–Madison, was recently honored with the Trewartha Senior Honors Thesis Research Award from the College of Letters & Science (L&S). The grant recognizes outstanding undergraduate research proposals and empowers L&S Honors Program students to conduct more extensive senior Honors thesis research projects than would otherwise be possible. “The award is an encouragement of my aspiration to develop applicable statistical tools to address practical problems,” Zhao said. Zhao explained that her project explores “how missing data affects predictions of whole-body donation acceptance in the UW–Madison School of Medicine and Public Health Body Donor Program.” The Body Donor Program enables individuals to donate their bodies for hands-on medical education for UW–Madison students, including future medical doctors, physical and occupational therapists, and physician assistants. Specifically, Zhao is interested in how missing data related to demographic information, such as education or occupation, may affect the accuracy of the statistical models used to predict acceptance into the program. Sometimes, she explained, such data may be missing due to underlying factors related to the individual’s circumstances, rather than random chance. This missing data, Zhao said, is referred to as “Missing Not at Random (MNAR),” meaning that “the missingness is influenced by unobserved factors.” For instance, for various reasons, some people may be unwilling to report their level of education, an omission that can lead to what Zhao called “incorrect predictions about donor acceptance.”  In other words, the missing data can lead the statistical model to erroneously predict someone as being declined from the program, when in reality they should be accepted (even with some data missing). These misleading predictions can ultimately affect decision-making about whether to accept a person’s body into the Body Donor Program. “Incorrectly predicting someone as declined may risk losing a potential full-body donation, which is a loss for medical education, research, and clinical training,” Zhao said. This is a key issue she hopes to address through her research. She also noted that this work pursues an understudied topic which deserves more scholarly attention. “There is not enough emphasis on testing data as MNAR. It is common to assume missing data is Missing at Random, however, practical scenarios like the Body Donor Program are often more complex than that. Testing MNAR adds to the comprehensiveness of analysis and decision making, and I hope to emphasize its importance through my work.” Zhao expressed gratitude to several Department of Statistics faculty members for their support and guidance in shaping her winning proposal.
  • Professor Rick Chappell: “He spent months guiding me through introductory materials in the field, providing countless examples that made complex concepts easy to understand and unforgettable. Professor Chappell remembers my interests and continually connects me to resources and opportunities that enable me to explore them further,” Zhao said.
  • Assistant Professor Kris Sankaran and Associate Professor Hyunseung Kang: “Their amazing lectures and patient guidance during office hours helped me build strong visualization and regression analysis skills, which I applied extensively in my project.”
  • Chair and Professor Bret Larget: “He provided me with invaluable advice on the technical details involved in this work.”
Zhao’s work is an example of how statisticians at UW–Madison, including undergraduate students, are often indispensable contributors to interdisciplinary research. As she prepares to delve more deeply into this research in the spring, Zhao is looking forward to the discoveries and lessons encountered along the way. “There are many more exciting things waiting for me to learn and explore,” she said. “I will continue to take every step steadily and enjoy the process.” As a recipient of the Trewartha award, Zhao will present her findings at the 2025 L&S Honors Senior Thesis Symposium this spring and plans to pursue further research through graduate education in statistics or biostatistics after graduation.
Learn more about the L&S Trewartha Senior Honors Thesis Research Award. Explore more about our Undergraduate Statistics Major.