The Biostatistics Core is a new core designed to serve as a centralized resource for biostatistical and biomathematical expertise to support AIDS research at UCLA. The aims of the Biostatistics Core are to enhance HIV/AIDS research and to establish and foster long term collaborations between clinical, basic and behavioral researchers and biostatisticians at UCLA. This collaboration will lead to an improvement in the biostatistical and biomathematical aspects of the AIDS research undertaken at UCLA. The existence of the core will ensure that AIDS investigators have ready access to expert statistical consultation and support, and that the most appropriate and up-to-date methods are used. The Biostatistics Core will provide assistance to AIDS investigators in the following areas (i) study design, (ii) data analysis (iii) mathematical modelling, (iv) protocol development, (v) grant applications, (vi) advice on data-base structures, (vii) manuscript preparation and (viii) and statistical methods research to facilitate the analysis of HIV/AIDS data. There will be two levels of activity of the Biostatistic Core. One will be faculty level long term scientific research collaboration between faculty members in the department of Biostatistics or Biomathematics and AIDS researchers at UCLA. The other will be Staff or M.S. level consulting on AIDS research problems under faculty supervision or with faculty involvement. A consequence of the emphasis on long-term collaborative interactions is that this will lead to grant submissions and funding from other sources, thus allowing the Biostatistic Core to be available to focus on establish new collaborations and supporting new research.