ABSTRACT The role of the Biostatistics Core is to support the investigators of the Leukemia SPORE in their research efforts, including laboratory experiments, molecular studies, and analysis of clinical trial and correlative data. Prior to the initiation of all studies, Core staff will consult with SPORE investigators to discuss the underlying scientific premise and translational goals of the project, to help the investigators select the most efficient and robust analytical methods, and to estimate sample sizes to ensure adequate power to address study objectives. In laboratory experiments, Core members will assist in the formulation of the experimental design and in the analysis and interpretation of the data at the conclusion of the study. For molecular studies using human tissues, Core members will closely interface with the members of the Genomics Core and will have primary responsibility for merging molecular and clinical data, and for performing appropriate statistical and bioinformatics analyses. The members of the Biostatistics Core will also work with SPORE investigators to format data for publication and assist with deposition of genomic data into public repositories to facilitate validation of results by external investigators using their own analytical methods. For clinical studies, they will work with SPORE investigators to help set up effective systems to collect and track all required data. As the research project (RP) studies proceed, Core staff will review project databases and monitor the quantity and quality of data collected, and they will suggest modifications to the design and analysis plans as appropriate. When studies are finished, the Core will conduct correct and efficient data analyses. They will also assist investigators with the preparation of any necessary graphs and tables, the interpretation of results, the preparation of presentations and manuscripts, and will consult on the design of subsequent research. If current statistical methodology does not adequately address a research question, alternative methodologies will be developed. We believe that this experienced and collaborative Core is well configured to provide the SPORE with a high level of statistical leadership and support that will enhance the efficiency, quality, and quantitative rigor of its science.