Dr. Heller's current research interests include the design and analysis of phase II clinical trial data and the analysis of survival data. For the analysis of a phase II study, he has developed a test statistic that adjusts for patient risk and improves the accuracy of the test for treatment efficacy relative to conventional tests. In survival analysis, Dr. Heller developed a method to employ the proportional hazards model when the endpoint is progression-free survival. The methodology is based on the recognition that the true progression time is not observed, but is known to lie in an interval between the last negative test and the first positive test. Dr. Heller is involved in the design and analysis of laboratory and clinical studies emanating from the Departments of Medicine, Pediatrics, and Surgery. In addition, he is the Principal Investigator for the Biostatistics Core in NIH program projects in Bone Marrow Transplantation, and the Prostate SPORE.