The Statistics and Data Management Core will be responsible for the majority of data management associated with the Center. It will also provide consultation on data analysis to all of the projects, in particular with regard to multilevel models and scale construction. Under the supervision of the Core Director, Dr. Berbaum, core staff will develop procedures for acquiring, validating and merging data sets from the multiple data sources which will contribute data to the Center. Core personnel will establish close liaisons with the Survey Research Laboratory to ensure the smooth transmission of data files. A secure web site will be constructed in order to allow Center investigators to obtain data files in an efficient manner. The Core will implement HRPC Data Management Standards and Confidentiality procedures with regard to all data. With regard to data analysis, the Core staff will assist investigators and their staff's in devising data analysis procedures which are at the highest level possible. Core staff are well known experts in such areas as multilevel models, structural equation modeling and item response theory. Much of the analysis generated by the various projects will require the use of these techniques, particularly multilevel models. Given the rapid rate of change in this field, a particularly important task for the Core will be to keep individual investigators appraised of developments in statistical methodology and software.