The Archive collects data in two forms: court-level aggregate statistics and detailed case-level data. Court-level aggregate statistics either are abstracted from the annual reports of State and local courts or are contributed directly to the Archive. Court-level statistics typically provide counts of the delinquency and status offense cases handled by courts in a defined time period (calendar or fiscal year).

Case-level data are usually generated by automated client-tracking systems or case-reporting systems managed by juvenile courts or other juvenile justice agencies. These systems provide detailed data on the characteristics of each delinquency and status offense case handled by courts, generally including the age, sex, and race of the youth referred; the date and source of referral; the offenses charged; detention; petitioning; and the date and type of disposition.

The structure of each data set contributed to the Archive is unique, having been designed to meet the information needs of a particular jurisdiction. Archive staff study the structure and content of each data set in order to design an automated restructuring procedure that will transform each jurisdiction's data into a common case-level format.

The aggregation of these standardized case-level data files constitutes the Archive's national case-level database. The compiled data from jurisdictions that contribute only court-level statistics constitute the national court-level database. Together, these two multijurisdictional databases are used to generate the Archive's national estimates of delinquency and status offense cases.

Each year, juvenile courts with jurisdiction over more than 97% of the U.S. juvenile population contribute either case-level data or court-level aggregate statistics to the Archive. However, not all of this information can be used to generate the national estimates contained in JCS. To be used in the development of national estimates, the data must be in a compatible unit of count (i.e., case disposed), the data source must demonstrate a pattern of consistent reporting over time (at least 2 years), and the data file contributed to the Archive must represent a complete count of delinquency and/or status offense cases disposed in a jurisdiction during a given year.

In 1997, case-level data describing 917,446 delinquency cases handled by 1,457 jurisdictions in 27 States met the Archive's criteria for inclusion in the development of national estimates. Compatible data were available from Alabama, Arizona, Arkansas, California, Connecticut, Florida, Illinois, Kentucky, Maryland, Michigan, Minnesota, Mississippi, Missouri, Montana, Nebraska, New Jersey, New York, North Dakota, Ohio, Pennsylvania, South Carolina, South Dakota, Tennessee, Utah, Virginia, Washington, and West Virginia. These courts had jurisdiction over 54% of the Nation's juvenile population in 1997. Compatible court-level aggregate statistics on an additional 217,441 delinquency cases from 584 jurisdictions were reported from the District of Columbia and the States of California, Hawaii, Idaho, Illinois, Indiana, New York, Oklahoma, Texas, and Vermont. In all, the Archive received compatible case-level data and court-level statistics on delinquency cases from 1,983 jurisdictions containing 71% of the Nation's juvenile population in 1997 (table 86).

Case-level data describing 88,433 formally handled status offense cases from 1,531 jurisdictions in 27 States met the estimation criteria for 1997. The contributing States were Alabama, Arizona, Arkansas, California, Connecticut, Florida, Illinois, Iowa, Kentucky, Maryland, Michigan, Minnesota, Mississippi, Missouri, Montana, Nebraska, New York, North Dakota, Ohio, Pennsylvania, South Carolina, South Dakota, Tennessee, Utah, Virginia, Washington, and West Virginia. These courts had jurisdiction over 52% of the juvenile population. An additional 521 jurisdictions in 7 States (California, Hawaii, Idaho, Indiana, Oklahoma, Texas, and Vermont) and the District of Columbia reported compatible court-level aggregate statistics on 13,557 petitioned status offense cases. Altogether, compatible case-level and court-level data on petitioned status offense cases were available from 2,052 jurisdictions containing 68% of the U.S. juvenile population (table 87).