The availability of computer-readable resources through a social science data archive serves both a scientific and an administrative function based upon the concept of secondary or extended analysis. The underlying notion of secondary analysis is that no principal investigator ever exhausts the full analytic potential of a dataset. From a scientific perspective, the significance of archival data rests upon the principle of replication; confidence in the validity of a relationship between two or more variables is increased by the number of times and variety of settings in which it can be reproduced. From an administrative point of view, archival resources represent a cost-effective means of increasing research opportunities and, implicitly, results. A variety of computer-readable data resources for the study of crime and the criminal justice system may already be available through several different sources, including Federal agencies and various academic data organizations. The growth of non-Federal data archives can be directly attributed to the difficulties which researchers have encountered in acquiring and analyzing data resources from Federal agencies and individual researchers.