Data schema

CJARS is a nationally integrated repository of criminal justice data using administrative records held by agencies in a wide array of formats and coding schemes. To maximize its research potential, CJARS is being built with a target national data schema, which guides strategies for record linkage and harmonization.

Creating a national schema

Understanding how different agencies collect, organize, and store their criminal history information is key to building a national repository of criminal justice data. In an effort to better understand data inventories, structures, and maintenance, we requested available documentation about the collections, storage, and organization of criminal history data from all U.S. states and territories. Responses were used to generate a national data schema that strikes a balance between careful treatment of jurisdictional differences and research usability.

A simplified schema

CJARS organizes its data into five relational tables that each cover major criminal justice processes (see figure below). The data are separated into a relational table to increase the tractability of each table. Records belonging to an individual can be linked across different data sets using a master person file.