Abdus S Wahed, PhD

My current major research interest is in personalized medicine – development of statistical methods for testing dynamic treatment regimes (adaptive treatment strategies) through sequentially randomized designs, for screening viable treatment regimes from observational data, and for identifying important variables for forming dynamic treatment regimes. Other methodological research interest includes multivariate ordinal longitudinal data analysis, survival analysis in the presence of misclassified events, and analysis of variance for censored survival data, length biased data, and joint modeling of longitudinal and time-to-event data measured with error. My collaborative research interest includes development of multi-stage depression treatment regimes, sequential treatment decisions in depression treatment, development of risk scores for complications in bariatric surgery, analysis of outcomes in hepatitis B and C clinical trials and cohort studies, and weight loss in young adults.

Ph.D., Statistics (2003), North Carolina State University, Raleigh, NC
M.A., Mathematical Statistics (2000), Ball State University, Muncie, IN
M.Sc., Statistics (1994), University of Dhaka, Bangladesh
B.Sc., Statistics (1992, Minor: Economics and Mathematics), University of Dhaka, Bangladesh

Linear Models

Estimation Theory

Likelihood Theory

1. *Jiang, Z, Liu, Y, Wahed, AS, and Molenberghs, G (2018). Joint modeling of multiple ordinal adherence outcomes via generalized estimating equations with flexible correlation structure.
Statistics in medicine 37 (6), 983-995.
2. *Adeniji, AK, Hsu, JY, Wahed, AS (2018). Estimation of discrete survival function for error-prone diagnostic tests. Pharmaceutical statistics 17 (1), 74-89.

3. Yavuz, I, Cheng, Y, and Wahed, AS (2018). Estimating the Cumulative Incidence Function of Dynamic Treatment Regimes. Journal of Royal Statistical Society, Series A. 181 (1), 85-106.

4. *Buhule, OD, Wahed, AS, and Youk, AO (2017). Bayesian hierarchical joint modeling of repeatedly measured continuous and ordinal markers of disease severity: Application to Ugandan diabetes data. Statistics in medicine 36 (29), 4677-4691.

5. *Hsu JY, Wahed AS (2017). Weighted generalized estimating equations for response-adaptive treatment regimes in two-stage longitudinal studies. Journal of Statistical Research 51(1): 79-100

6. Xu, Y, Mller, P, Wahed, AS, and Thall, PF. (2016). Bayesian Nonparametric Estimation for Dynamic Treatment Regimes with Sequential Transition Times; In Press, J. of the Am. Stat. Assoc. 111 (515), 921-950.

7. *Sampene, E. and Wahed, AS (2016). A Relatively Simple Efficient Estimator for Relative Risk in Case-Cohort Studies. Journal of Statistical Research 2016, Vol. 48-50, No. 2, pp. 37-54

8. *Marron, MM, and Wahed, AS (2016). Teaching Missing Data Methodology to Undergraduates Using a Group-Based Project Within a Six-Week Summer Program. Journal of Statistics Education 24 (1), 8-15.

9. Jaman, A, Latif, AHMM, Bari, W, and Wahed, AS (2016). A determinant-based criterion for working correlation structure selection in generalized estimating equations. Statistics in Medicine, Volume 35, Issue 11, 20 May 2016, Pages 18191833.

10. *Ogbagaber, SB, Karp, J, and Wahed, AS (2016). Design of sequentially randomized trials for testing adaptive treatment strategies. Statistics in Medicine. Volume 35, Issue 6, pp 840-858.

11. *Dong, X, Kong, L, and Wahed, AS (2015). Accelerated failure time model for case-cohort design with longitudinal covariates subject to measurement error and detection limits. Statistics in Medicine, Volume 35, Issue 8 pp 1327-1339.
12. *Tang, X, and Wahed, AS (2015). Pattern-mixture-type Estimation and Testing of Neuroblastoma Treatment Regimes. Journal of Statistical Theory and Practice Vol 9, Issue 2, pp 266-287.

13. Huang, X, Ning, J,Wahed, AS (2014). Optimization of individualized dynamic treatment regimes for recurrent diseases. Statistics in medicine 33.14 (2014): 2363-2378.

14. *Kidwell, K, Ko, JH, and Wahed, AS (2014). Inference for the median residual life function in sequential multiple assignment randomized trials. Statistics in medicine 33.9 (2014): 1503-1513.

15. *Adeniji, A, Belle, SH, and Wahed, AS (2014). Incorporating diagnostic accuracy into the estimation of discrete survival function. Journal of Applied Statistics 41.1 (2014): 60-72. Volume 41, Issue 1, 2014, PP 60-72

16. *Tang, X, and Wahed, AS (2014). Cumulative Hazard Ratio Estimation for Treatment Regimes in Sequentially Randomized Clinical Trials. Statistics in Biosciences, 10.1007/s12561-013-9089-6

17. *Kidwell, KM and Wahed, AS (2013). Weighted Log-rank Statistic to Compare Shared-Path Adaptive Treatment Strategies. Biostatistics 2013 Apr;14(2):299-312.

18. Wahed, AS, Thall, PF(2013 ). Evaluating Joint Eects of Induction-Salvage Treatment Regimes on Overall Survival in Acute Leukemia. Journal of Royal Statistical Society, Series C. Appl. Statist. (2013) 62, Part 1, pp. 6783

19. *Miyahara, S, and Wahed, AS (2012). Assessing the Eect of Treatment Regimes on Longitudinal Outcome Data: Application to REVAMP Study of Depression. Journal of Statistical Research. Vol. 46 (2), 233-254

20. *Ko, JH, and Wahed, AS (2012). Up-front vs. Sequential Randomizations for Inference on Adaptive Treatment Strategies. Statistics in Medicine, Volume 31, Issue 9, pages 812830

21. *Tang, X, andWahed, AS (2011). Comparison of Treatment Regimes with Adjustment for Auxiliary Variables. Journal of Applied Statistics, 2011; 38: 2925-2938.
22. Wahed, AS (2011). On the Equivalence of Inverse-Probability-of-Censoring-Weighted and Kaplan-Meier Estimators. Invited Article, Journal of Applied Statistical Sciences, Volume 18, Issue 4.
23. *Miyahara, S, and Wahed, AS (2010). Weighted Kaplan-Meier Estimators for Two-Stage Treatment Regimes. Statistics in Medicine, 2010; 29: 2581-2591.
24. Wahed, AS(2010). Inference for Two-Stage Adaptive Treatment Strategies Using Mixture Distributions. Journal of Royal Statistical Society Series C (Applied Statistics) Appl. Statist. (2010) 59.

25. *Feng, W and Wahed, AS (2009). Sample Size for Two-Stage Studies with Maintenance Therapy. Statistics in Medicine, 2009; 28: 2028-2041

26. Wahed, AS ,Luong, T, and Jeong, J-H (2009). A new generalization of Weibull distribution with application to a breast cancer data set. Statistics in Medicine, 2009; 28: 2077-2094

27. Wahed, AS (2009). Estimation of survival quantiles in two-stage randomization designs, Journal of Statistical Planning and Inference 139 (2009) 2064-2075.

28. *Feng, W and Wahed, AS (2008). A supremum log rank test for comparing adaptive treatment strategies and corresponding sample size formula, Biometrika. 95, 3, pp. 695-707.

29. Ali, MM, Woo, J, Pal, M and Wahed, AS (2008). Some Skew-Symmetric Double Inverted Distributions. International Journal of Statistical Sciences. Vol. 7, pp. 1-12.
30. Wahed, AS (2007). The family of curvi-triangular distributions. International Journal of Statistical Sciences, Vol 6, pp 7-18.

31. Wahed, AS and Tsiatis, AA (2006). Semi-parametric Efficient Estimation of The Survival Distribution for Treatment Policies in Two-Stage Randomization Designs in Clinical Trials with Censored Data. Biometrika Vol 93: pp. 147-161.

32. Wahed, AS (2006). Bayesian Inference Using Burr Model Under Asymmetric Loss Function: An Application to Carcinoma Survival Data. Journal of Statistical Research, 2006, Vol. 40, No. 1, pp. 45-57.