Dr. Su is interested in many topics of statistics. His primary research areas in statistical methodology include tree-structured models or recursive partitioning, variable selection, causal inference, data mining, and machine learning. He has also been actively collaborating in a wide range of application areas including quality of life research among breast cancer survivor, tooth prognosis in dental research, the associative effect of testosterone/cortisol on child health and development, brain cancer, alcohol abuse treatment and intervention, HIV studies, transportation safety research, and prostate cancer. diagnosis/prognosis.