The Data Documentation, Outreach, and Security Core of the Wisconsin Longitudinal Study (WLS) will be responsible for creating, documenting, disseminating, and maintaining the security and confidentiality of WLS data. Plans for data creation, documentation, dissemination, and security will be developed with advice from the WLS Steering Committee, and in consultation with the Data Monitoring Board. The goals and activities of this Core are as follows: (1) to create clean, user-friendly data files for public use and archival storage at ICPSR and for private and secured analytic use; (2) to create hierarchically organized documentation that is correct, clear, thoroughly cross-referenced, portable, and accessible on the internet; (3) to create, document, and support data access tools to facilitate variable choice and variable and case extraction; (4) to respond quickly to user-identified data problems by validating and, if need be, correcting and documenting them; (5) to maintain a central bibliographic record of WLS publications and, to the extent possible, of full text in electronic form; (6) to publicize and encourage use of WLS data products using the internet (project web-site, strategically located links, and e-mail), traditional publication outlets, and presentations and displays at scientific meetings; (7) to sponsor and organize local and extramural seminars and workshops to demonstrate the access and use of WLS data and to report research in progress; (8) to organize a small project competition and workshops to encourage innovative uses (and new users) of WLS data; and (9) to create, manage, and protect highly confidential data files, e.g., those including private data from administrative records, and facilitate indirect use of those files in the secure data enclave of the Center for Demography of Health and Aging.