ABSTRACT The Biostatistics Core provides long-term collaborative support to established programs of research at the Cancer Center, and short-term consulting services. The work of the Core enhances the scientific objectives of the Center?s research programs by providing expertise on study design and statistical analysis. The field of biostatistics is devoted to developing an understanding of the appropriate ways to derive scientific inferences from quantitative data, and to developing methods for achieving this aim. The staff is highly trained in this field and were all recruited after extensive national searches. The Core consists of 19 doctoral-level faculty biostatisticians, assisted by 16 masters-level biostatisticians, 1 bachelor-level biostatistician, and a team of programming staff and administrative staff. The doctoral-level biostatisticians in the Core have broad, collective experience in all of the specialized areas of statistical techniques that are pertinent to contemporary cancer research, including clinical trials methodology, survival analysis, epidemiologic methods, analysis of genomics data, statistical genetics, methods for diagnostic medicine, evidence-based medicine and psychometric methods. Cost recovery is achieved primarily through involvement of the Core members and staff as funded co-investigators on NIH grants. By providing a valid framework for the design, conduct and analysis of scientific studies, the Core contributes to scientific quality and promotes interdisciplinary research. The broad range of services and collaborative work provided by the Biostatistics Core has supported the research of 482 investigators in the past year. During the past grant period the work of the Core has contributed to 2,539 publications of researchers from 9 research programs. For example, the Biostatistics Core developed a method called FACETS to infer copy number alterations from the institution?s IMPACT sequencing assay. FACETS has quickly become part of the standard toolkit of genomic analysis at MSK.