The Biostatistics Core will provide data managed, analysis and consultation services for design and analysis issues that arise in all the projects. In addition, core statisticians will conduct original research in new methods to be applied to data from these projects. The core will also provide a repository for data from these projects, and will maintain Internet services such as project-specific mailing lists and a Web server providing access to public information on project findings and protected information such as progress reports and manuscripts. These activities include: 1. Data management: The core will serve as a coordinating center for data. 2. Statistical analysis: Core statisticians will design and conduct statistical analysis for all projects, provide assistance in selection of appropriate methods, check assumptions for particular methods and develop summaries of results. Core statisticians are experienced in developing new statistical methods for epidemiologic studies, and will work with each project to ensure that appropriate methods are used. 3. Statistical consulting: The core will participate in design of data collection instruments to insure validity, internal consistency and compatibility with data management and statistical analysis requirements. In addition, core statisticians will provide consultation services to investigations in all projects to assist in experimental design, choice of analysis methods and interpretation of results. The core statisticians will also provide statistical consultation in designing proposals for future SFCRC proposals, and for SFCRC pilot project grantees for aid in planning analyses and interpretation of results. 4. Research. The core will conduct research on statistical methods for application to all projects. 5. Information exchange: In addition to maintaining project datasets, the core will set up and maintain a number of Internet services to provide project personnel with secure access to analyzable datasets, progress reports and manuscripts, and project-specific e-mail distribution.