Biostatistics and Data Validation Scientific Core: Abstract The overall goal of the Biostatistics and Data Validation (BDV) Scientific Core is to ensure scientific rigor, reliability of results, and reproducibility of research undertaken within the proposed Program, entitled, ‘Multi- Scale Evaluation and Mitigation of Toxicities Following Internal Radionuclide Contamination’. While the interdisciplinary nature and synergies of this Program are unique strengths, it can also present challenges for integration between research projects at different institutions, particularly with regard to standardized data management and statistical approaches. As such, the BDV Core will provide integrated support for statistical design and analyses, source term characterization, data management, and validation of models and findings. Principal Investigators (PIs) from collaborating institutions will have ready access to the team of biostatisticians, radiation subject matter experts, and medical practitioners for the coordination, verification, and execution of research experiments, data management, and analyses. The BDV Core will collaborate closely with research project PIs to ensure that sound experimental designs, statistical methodologies, and radiological source terms are utilized and documented, a critical factor in assuring that results are reliable and reproducible. A unique aspect of this Core is the implementation of strategic validation and bench-marking processes, accomplished by identifying appropriate datasets or results from literature, models, and other available sources for use in sensitivity analyses and comparisons to confirm that inferences and results from the Program are consistent with known or previously reported findings. This effort, coupled with clinical perspective provided by radiation medicine experts, is critical to ensuring integrity of research results and products while promoting translation into practice for in-field radiation protection, medical management of radiation exposure and injury, and use of medical countermeasures. Further, centralized management of the Program data repository by the BDV Core, with oversight from the Program Administrative Core, will ensure data integrity, accessibility, and version control. In conclusion, the integrated expertise in biostatistics, radiation source term characterization, validation analyses, and data management provided by the BDV Core will provide valuable scientific support for the successful completion of the proposed research projects in the Program.