In Year 13, the Biology Core will work closely with the Data Collection subproject and Dissemination Core to monitor all aspects of main study biological data collection and the resulting specimen archive. The Biology Core will have primary responsibility for monitoring the quality and reliability of biological specimens and data, including anthropometric measurements, medication inventory data, and assay results. The Core will also oversee systems for the tracking, storage and archiving of biological samples. By reviewing data distributions and value ranges, the Biology Core will assist the Dissemination Core in data cleaning and dissemination. The Biology Core will also provide documentation of data collection protocols, specimen collection and biological measures to the Dissemination Core for distribution to data users. To ensure that the science produced with the biological data from Add Health is consistent with the scientific goals of our project, the Biology Core will continue to evaluate proposals by researchers seeking to use archived biological specimens. Reviews will be submitted to the Project Director, who, in collaboration with the Deputy Director and Biology Core Pis, will decide whether to grant and/or recommend changes in the researcher's request. Throughout Year 13, the Biology core will continue to provide scientific guidance and advice for the integration of biological paradigms and data into subproject theoretical models and analysis plans. Scientific guidance and advice will occur through mutual work and collaboration among Biology Core members and Program Investigators. The Biology Core will also assist in the preparation of research methods papers based on the results of the cortisol and incentive experiments embedded in the Wave IV pretest.