His research interests in statistical methods development center around sequential methodology and adaptive designs with applications to clinical trials and other medical studies; robust methods for multidimensional outcomes, design, analysis, and evaluation of complex biomarkers in diagnosis and prediction of diseases; and methods for semicontinuous outcomes, such as episodically consumed foods.

Dr. Liu is an active member of several professional societies, including the American Statistical Association (ASA) and the International Chinese Statistical Association (ICSA). He is an elected fellow of ASA and has served a number of positions in ICSA.