Research Associate Professor, Survey Research Center, Institute for Social Research, Research Associate Professor, Biostatistics, School of Public Health and Adjunct Lecturer in Quantum Methods and Social Science Program, College of Literature, Science, and the Arts

Biography
Yajuan Si is a Research Associate Professor in the Survey Methodology Program, located within the Survey Research Center at the Institute for Social Research on the University of Michigan-Ann Arbor campus. She received her Ph.D on Statistical Science in 2012 from Duke University. Before joining the University of Michigan in 2017, Yajuan was an assistant professor jointly in the Department of Biostatistics & Medical Informatics and the Department of Population Health Sciences at the University of Wisconsin-Madison and a Postdoctoral Research Scholar in the Department of Statistics at Columbia University. Dr Si’s research lies in cutting-edge methodology development in streams of Bayesian statistics, complex survey inference, missing data imputation, causal inference, and data confidentiality protection. Yajuan has extensive collaboration experiences with health services researchers and epidemiologists to improve healthcare and public health practice, and she has been providing statistical support to solve sampling and analysis issues on health and social science surveys.
Projects
Funded Research
- A Development of Exemplars of Non-Response Bias Analysis for NCES Data Collections
- Assessing the interactive effect of lifetime and old age cognitive engagement on cognitive decline and dementia: cognitive reserve versus use it or lose it
- Child Mind Institute: Survey Methodology
- Enhancing Synthetic Data Techniques for Practical Applications
- Novel Approaches to Adjusting for Population Heterogeneity and Representation in Neuroimaging Studies
- Statistical adjustments of sample representation in community-level estimates of COVID-19 transmission and immunity
- The Healthy Brain and Child Development National Consortium Administrative Core
Publications
- Brady Thomas West, Yajuan Si, Hu,Yueying, Sean Esteban McCabe, Philip Todd Veliz. 2024. The role of weighting adjustment for attrition in longitudinal trajectory modeling: a simulation study. Communications in Statistics - Simulation and Computation
- Yajuan Si, Heeringa,Steven G, Johnson, David, Roderick J Little, Liu, Wenshuo, Fabian T Pfeffer, Trivellore E Raghunathan. 2023. Multiple Imputation with Massive Data: An Application to the Panel Study of Income Dynamics. Journal of Survey Statistics and Methodology 11(1):260-283.
- Yajuan Si, Sunghee Lee, Steven G Heeringa. 2023. Population Weighting in Statistical Analysis. JAMA Internal Medicine 184(1):98-99.
- Katherine Li, Yajuan Si. 2023. Embedded multilevel regression and poststratification: Model-based inference with incomplete auxiliary information. Statistics in Medicine 43(2):256-278.
- Shivani Bakre, Nicholas Moloci, Norton,Edward C, Valerie A. Lewis, Yajuan Si, Sunny Lin, Emily J. Lawton, Lindsey A. Herrel, John M. Hollingsworth. 2022. Association Between Organizational Quality and Out-of-Network Primary Care Among Accountable Care Organizations That Care for High vs Low Proportions of Patients of Racial and Ethnic Minority Groups. JAMA Health Forum 3(4):e220575.
- Yajuan Si, Brady Thomas West, Philip Todd Veliz, Megan E Patrick, John E Schulenberg, Deborah Denise Kloska, Yvonne M Terry-McElrath, Sean Esteban McCabe. 2022. An empirical evaluation of alternative approaches to adjusting for attrition when analyzing longitudinal survey data on young adults’ substance use trajectories. International Journal of Methods in Psychiatric Research
- Schumacher, Jessica R, Neuman, Heather B, Yu, Menggang, Vanness, David J, Yajuan Si, Burnside, Elizabeth S, Ruddy, Kathryn J, Partridge, Ann H, Schrag, Deborah, Edge, Stephen B, Zhang, Ying, Jacobs, Elizabeth A, Havlena, Jeffrey, Francescatti, Amanda B, Winchester, David P, McKellar, Daniel P, Spears, Patricia A, Kozower, Benjamin D, Chang, George J, Greenberg, Caprice C. 2022. Surveillance imaging vs symptomatic recurrence detection and survival in stage II-III breast cancer (AFT-01). JNCI: Journal of the National Cancer Institute 114(10):1371-1379.
- Yajuan Si, Roderick J Little, Ya Mo, Nell Sedransk. 2022. A Case Study of Nonresponse Bias Analysis in Educational Assessment Surveys. Journal of Educational and Behavioral Statistics
- Yajuan Si, Nicholas Moloci, Sitara Murali, Sarah Krein, Andy Ryan, John M. Hollingsworth. 2022. Use of Preventive Care Services and Hospitalization Among Medicare Beneficiaries in Accountable Care Organizations That Exited the Shared Savings Program. JAMA Health Forum 3(1):e214452.
- Jieun Song, Barry T. Radler, Margie E. Lachman, Marsha R. Mailick, Yajuan Si, Carol D. Ryff. 2021. Who Returns? Understanding Varieties of Longitudinal Participation in MIDUS. Journal of Aging and Health 33(10):896-907.
- Moloci, Nicholas M., Yajuan Si, Norton,Edward C, Ryan, Andrew M., Hollingsworth, John M.. 2021. Predicting Losses from Medicare Shared Savings Program Departures. Journal of General Internal Medicine 36(8):2490-2491.
- Yajuan Si, Zhou, Peigen. 2021. Bayes-Raking: Bayesian Finite Population Inference with Known Margins. Journal of Survey Statistics and Methodology 9(4):833-855.
- Ryan S. Hsi, David S. Goldfarb, Ada Egbuji, Yajuan Si, Vahakn Shahinian, John M. Hollingsworth. 2021. Comparison of Selective Versus Empiric Pharmacologic Preventative Therapy With Kidney Stone Recurrence. Urology 149:81-88.
- Covello, Leonard, Gelman, Andrew, Yajuan Si, Wang, Siquan. 2021. Routine Hospital-based SARS-CoV-2 Testing Outperforms State-based Data in Predicting Clinical Burden. Epidemiology 32(6):792-799.
- Kevin Constante, Edward Huntley, Yajuan Si, Emma Schillinger, Christine Wagner, Daniel P Keating. 2020. Conceptualizing protective family context and its effect on substance use: Comparisons across diverse ethnic-racial youth. Substance Abuse 42(4):796-805.
- Yajuan Si, Mari Palta, Maureen Smith. 2020. Bayesian profiling multiple imputation for missing hemoglobin values in electronic health records. The Annals of Applied Statistics 14(4):1903-1924.
- Yajuan Si, Rob Trangucci, Jonah Sol Gabry, Andrew Gelman. 2020. Bayesian hierarchical weighting adjustment and survey inference. Survey Methodology 46(2)
- Yajuan Si. 2020. Model-Based Inferences. SAGE Research Methods Foundations
- Yajuan Si, Makela, Susanna , Gelman, Andrew . 2018. Bayesian inference under cluster sampling with probability proportional to size. Statistics in Medicine 37(26):3849-3868.
- Schumacher, Jessica R., Neuman, Heather B., Chang, George J., Kozower, Benjamin D., Edge, Stephen B., Yu, Menggang, Vanness, David J., Yajuan Si, Jacobs, Elizabeth A., Francescatti, Amanda B., Spears, Patricia A., Havlena, Jeffrey, Adesoye, Taiwo, McKellar, Daniel, Winchester, David, Burnside, Elizabeth S., Greenberg, Caprice C.. 2018. A National Study of the Use of Asymptomatic Systemic Imaging for Surveillance Following Breast Cancer Treatment (AFT-01). Annals of Surgical Oncology 25(9):2587-2595.
- Eva H. DuGoff, Juhee Cho, Yajuan Si, Craig Evan Pollack. 2018. Geographic Variations in Physician Relationships Over Time: Implications for Care Coordination. Medical Care Research and Review 75(5):586-611.
- Yajuan Si, Makela, S , Gelman, A . 2017. Graphical Visualization of Polling Results. The Oxford Handbook of Polling and Polling Methods
- Yajuan Si, Early, D M, Berg, J K, Alicea, S , Aber, J L, Ryan, R M, Deci, E L. 2016. The impact of every classroom, every day on high school student achievement: Results from a school-randomized trial. Journal of Research on Educational Effectiveness 9:3-29.
- Yajuan Si, Neuman, Heather B, Schumacher, Jessica R, Francescatti, Amanda B, Adesoye, Taiwo , SB, Edge , ES, Burnside , DJ, Vanness , M, Yu , D, McKellar , DP, Winchester , Greenberg, Caprice C. 2016. Utility of Clinical Breast Exams in Detecting Local-Regional Breast Events after Breast-Conservation in Women with a Personal History of High-risk Breast Cancer. Annals of surgical oncology 23(10):3385-3391.
- Yajuan Si, Reiter, Jerome P, Hillygus, D S. 2016. Bayesian latent pattern mixture models for handling attrition in panel studies with refreshment samples. Annals of Applied Statistics 10(1):118-143.
- Yajuan Si, Reiter, Jerome P, Hillygus, D S. 2015. Semi-parametric Selection Models for Potentially Non-ignorable Attrition in Panel Studies with Refreshment Samples. Political Analysis 2017/01/04(1):92-112.
- Yajuan Si, Pillai, Natesh S, Gelman, Andrew . 2015. Bayesian Nonparametric Weighted Sampling Inference. Bayesian Analysis 10(3):605-625.
- Yajuan Si, Makela, Susanna , Gelman, Andrew . 2014. Statistical Graphics for Survey Weights. Revista Colombiana de EstadIstica 37(2):285-295.
- Yajuan Si, Reiter, Jerome P. 2013. Nonparametric Bayesian Multiple Imputation for Incomplete Categorical Variables in Large-Scale Assessment Surveys. Journal of Educational and Behavioral Statistics 38(5):499-521.
- Yajuan Si, Deng, Yiting , Hillygus, D S, Reiter, Jerome P, Zheng, Siyu . 2013. Handling Attrition in Longitudinal Studies: The Case for Refreshment Samples. Statistical Science 28(2):238-256.
- Yajuan Si, Reiter, JP . 2011. A Comparison of Posterior Simulation and Inference by Combining Rules for Multiple Imputation. Journal of Statistical Theory and Practice 5(2):335-347.