Sangbum Choi, Ph.D

Department of Statistics, Korea University

#323 College of Political Science and Economics Building

145 Anam-ro, Seongbuk-Gu, Seoul 02481, South Korea

E-mail: choisang[at]korea.ac.kr

Google scholar: https://bit.ly/3yPOD3m

ACADEMIC POSITION

• Professor, Department of Statistics, Korea University, 2016 - Present

• Visiting Scholar, Department of Statistics, NC State University, 2022-2023

• Assistant Professor, Division of Clinical and Translational Sciences & Department of Epidemiology, The University of Texas Health Science Center at Houston, 2013 - 2016

• Postdoctoral Research Fellow, Department of Biostatistics, The University of Texas MD Anderson Cancer Center, 2010 - 2013 (Academic mentor: Dr. Xuelin Huang)

EDUCATION

• Ph.D. in Statistics, University of Wisconsin at Madison, 2010

  • Thesis: Semiparametric transformation models based on degradation processes (Thesis advisor: Dr. Kjell A. Doksum)

• B.S. in Statistics & Mathematics, Seoul National University, 2003

RESEARCH INTEREST

Semiparametric methods; Survival analysis; Causal inference; Longitudinal data analysis; Dynamic treatment regimes; Degradation modeling; Bandit problems. 

TEACHING

• Undergraduate Courses:

  • STAT201: Calculus (S2018, S2019, S2020, S2021)

  • STAT221: Introductory Probability (S2017, S2021, S2024)

  • STAT302: Time Series Data Analysis (F2019, F2021, F2023, F2024)

  • STAT342: Regression Analysis (S2018, F2024)

  • STAT346: Statistical Data Science (F2019, F2020)

  • STAT401: Multivariate Data Analysis (F2018, F2019)

  • STAT407: Causal Inference (S2023)

• Graduate Courses:

  • STAT504: Linear Models (S2020)

  • STAT508: Nonparametric Statistics (S2016, S2018, S2024)

  • STAT512: Probability and Stochastic Processes (F2017, F2021)

  • STAT703: Survival Analysis (F2018, F2020, F2023)

  • STAT712: Longitudinal Data Analysis (F2019)

  • STAT801: Theoretical Statistics (F2016)

SELECTED JOURNAL PUBLICATION (Methodology)

1. Choi T, Choi S, Bandyopadhyay D (2024+). Rank-based inference for the accelerated failure time model with partially interval-censored data, Statistica Sinica, In Revision. 

2. Kim Y, Choi T, Park S, Choi S, Bandyopadhyay D (2024). Inverse-weighted quantile regression with partially interval-censored data, Biometrical Journal, Accepted. 

3. Choi T, Park H, Cho H, Choi S (2024). Interval-censored linear quantile regression, Journal of Computational and Graphical Statistics, Accepted. 

4. Lee J, Choi T, Choi S (2024). Censored broken adaptive ridge regression in high-dimension, Computational Statistics, In Print. 

5. Lee H, Lee J, Choi T, Kang J, Choi S (2023). Towards flexible time-to-event modeling: optimizing neural networks via rank regression, 26th European Conference on Artificial Intelligence (ECAI 2023, proceeding paper), 372, 1340-1347. 

6. Son D, Choi S, Kang S (2023). Quantile regression for competing risks data from stratified case-cohort studies: an induced-smoothing approach, Journal of Statistical Computation and Simulation, 93(8), 1225-1243.

7. Kim M, Choi S (2023). A GEE approach for the semiparametric accelerated lifetime model with multivariate interval-censored data, Communications for Statistical Applications and Methods, 30(4), 389-402.

8. Choi T, Lee H, Choi S (2023). Accountable survival contrast-learning for optimal dynamic treatment regimes. Scientific Reports, 13(1), 2250.

9. Choi S, Choi T, Lee HY, Han SW, Bandyopadhyay D (2022). Double-robust methods for difference in restricted mean lifetimes using pseudo-observations. Pharmaceutical Statistics, 21(6), 1185-1198. 

10. Kim Y, Choi T, Choi S (2022). Exploring modern machine learning methods to improve causal-effect estimation. Communications for Statistical Applications and Methods, 29(2), 177-191. 

11. Son M, Choi T, Shin SJ, Jung Y, Choi S (2022). Regularized linear censored quantile regression. Journal of the Korean Statistical Society, 51, 589-607.

12. Cho H, Lee D, Lee S, Choi S. (2022). Applications of competing risks analysis in public health, Journal of the Korean Statistical Society, 51, 1-24.

13. Choi S, Choi T, Cho H, Bandyopadhyay D (2022). Weighted least-squares regression with competing risks data. Statistics in Medicine, 41(2), 227-241.

14. Choi T, AKH Kim, Choi S (2021). Semiparametric least-squares regression with doubly-censored data. Computational Statistics and Data Analysis, 164, e107306.

15. Choi T, Choi S (2021). A fast algorithm for the accelerated failure time model with high-dimensional time-to-event data. Journal of Statistical Computation and Simulation, 91(16), 3385-3403. 

16. Choi S, Huang X (2021). Efficient inferences for linear transformation models with doubly censored data. Communications in Statistics-Theory and Methods, 50, 2188-2200.

17. Zhu L, Choi S, Li Y, Huang X, Sun J, Robison LL (2019). Statistical analysis of clustered mixed recurrent-event data with application to a cancer survivor study. Lifetime Data Analysis, 26, 820-832.

18. Choi S, Cho H (2019). Accelerated failure time models for the analysis of competing risks. Journal of the Korean Statistical Society, 48, 315-326.

19. Choi S, Kim C, Zhong H, Ryu ES, Han SW (2019). Adjusted-crude-incidence analysis of multiple treatments and unbalanced samples on competing risks. Statistics and Its Interface, 12, 423-437.

20. Choi S, Zhu L, Huang X (2018). Semiparametric accelerated failure time cure rate mixture models with competing risks, Statistics in Medicine, 37, 48-59.

21. Choi S, Kang S, Huang X (2018). Smoothed quantile regression analysis of competing risks. Biometrical Journal, 60, 934-946.

22. Choi S, Huang X, Ju H, Ning J. (2017). Semiparametric joint accelerated intensity models for correlated recurrent and terminal events. Statistica Sinica, 27, 625-643.

23. Huang X, Yan F, Ning J, Feng Z, Choi S, Cortes J. (2016). A two-stage approach for dynamic predictions of time to event using longitudinal biomarker data. Statistics in Medicine, 35, 2167-2182.

24. Huang X, Choi S, Wang L, Thall P. (2015). Optimization of multi-stage dynamic treatment regimes utilizing accumulated data. Statistics in Medicine, 34, 3424-3443.

25. Choi S, Huang X, Cormier JN, Doksum KA. (2014). A semiparametric inverse-Gaussian model and inference for survival data with a cured proportion. Canadian Journal of Statistics, 42, 635-649.

26. Choi S, Huang X, Cormier JN. (2014). Efficient semiparametric mixture inferences on cure rate models for competing risks, Canadian Journal of Statistics, 43, 420-435.

27. Choi S, Huang X. (2014). Maximum likelihood estimation of semiparametric mixture component models for competing risks data. Biometrics, 70, 588-598.

28. Choi S, Huang X. (2012). A general class of semiparametric transformation frailty models for non-proportional hazards survival data. Biometrics, 68, 1126-1135.

CONFERENCE PRESENTATION

• "Interval-censored linear rank regressions", The 12th ICSA International Conference, 2023

• "Interval-censored linear rank regressions", Department of Biostatistics, Virginia Commonwealth University, 2022

• "Partly interval-censored rank regressions", Bernoulli-IMS 10th WC, 2021

• "Nonparametric maximum likelihood estimation of accelerated failure time models for competing risks", CMStatistics, 2019

• "Double-robust inference for differences in restricted mean lifetimes using pseudo-observations", IASC-ISI, 2019

• "Doubly robust estimation of optimal dynamic treatment rules for discrete outcomes", IASC-ARS 25th Anniversary Conference, 2018

• "Analyzing competing risks data using accelerated failure time model", ICSA China Conference, 2018

• "Accelerated failure time model for recurrent events data", ICSA China Conference, 2016

• "A latent variable subgroup analysis of dependent competing risks data with application to a blood transfusion study", JSM Conference, 2015

• "Shrinkage nonparametric estimation of median survival time from censored data with applications to multicenter studies", JSM Conference, 2014

PROFESSIONAL AFFILIATION

American Statistical Association (ASA), International Biometric Society (IBS), Korean International Statistical Society (KISS), Korean Society of Statistics (KSS)

EDITORIAL SERVICE

• 2016 - Present: Associate Editor, Journal of the Korean Statistical Society

• 2018 - Present: Associate Editor, Managing Editor, Communications for Statistical Applications and Methods

OTHER PROFESSIONAL EXPERIENCE & CERTIFICATE

SOA (Society of Actuaries) Course I & II / FRM (Financial Risk Manager) / CFA (Chartered Financial Analyst) I

(Last updated: July 1, 2024)