My main research area has been time-to-event data analysis and clinical trials. In time-to-event data analysis, I have worked on frailty modeling, efficiency of survival probability estimates from the proportional hazards model, weighted log-rank test, competing risks, quantile residual lifetime, and likelihood theory such as empirical likelihood and hierarchical likelihood, which led to publication of my single-authored book with Springer, entitled Statistical Inference on Residual Life in 2014.
In clinical trials, I have been involved in several influential phase III breast cancer clinical trials, including work on developing a prediction model based on microarray data collected from different platforms, through the National Surgical Adjuvant Breast and Bowel Project (NSABP) as a co-investigator. I direct Data Management and Statistical Unit (DMSU) for the Division of General Academic Pediatrics, which also facilitates other senior investigators' research efforts in the Department of Pediatrics at large at Children’s Hospital of Pittsburgh of UPMC. I am also funded by Patient Centered Outcomes Research Institute (PCORI) projects, and collaborate with Cystic Fibrosis Center as a co-investigator. I am a senior faculty member in the Biostatistics, Epidemiology, Research and Design (BERD) core in the Clinical and Transnational Sciences Institute (CTSI) and in the Comparative Effectiveness Research Center (CERC) at University of Pittsburgh.
I have graduated 5 MS and 9 PhD students, and am currently advising 2 PhD students. I have been teaching statistical theory and survival analysis courses. I currently serve on the editorial board for the journal of Lifetime Data Analysis, a well-respected journal dedicated to time-to-event data analysis, and have been an elected member of the International Statistical Institute (ISI) since 2007.