The Juvenile Court Statistics (JCS) series uses data provided to the National Juvenile Court Data Archive (the Archive) by state and county agencies responsible for collecting and/or disseminating information on the processing of youth in juvenile courts. These data are not the result of a uniform data collection effort. They are not derived from a complete census of juvenile courts or obtained from a probability sample of courts. The national estimates presented in this Report are developed by using compatible information from all courts that are able to provide data to the Archive.

Sources of Data

The Archive collects data in two forms: court-level aggregate statistics and detailed case-level data. Courtlevel aggregate statistics either are abstracted from the annual reports of state and local courts or are contributed directly to the Archive. Courtlevel 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, gender, and race of the youth referred; the date and source of referral; the offenses charged; detention and petitioning decisions; 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 courtlevel statistics constitute the national court-level database. Together, these two multijurisdictional databases are used to generate the Archive’s national estimates of delinquency cases and to provide the sample of petitioned status offense cases.

Each year, many juvenile courts contribute either case-level data or courtlevel aggregate statistics to the Archive. However, not all of this information can be used to generate the national estimates contained in JCS.

Table A–1: 2002 Stratum Profiles for Delinquency Data       Counties reporting compatible data       Number of counties Stratum County population ages 10–17 Counties in stratum Case-level Court-level Total* Percentage of juvenile population 1 Fewer than 12,575 2,595 1,602 177 1,779     69% 2 12,575–53,250    353    198   35    233 69 3 53,251–133,700    104        61     8      69 70 4 More than 133,700      32       23     7      29 94 Total 3,084 1,884 227 2,110 75 * Some counties reported both case-level and court-level data; therefore, the total number of counties reporting delinquency data is not equal to the number of counties reporting case-level data plus the number of counties reporting court-level data.

Table A–2: 2002 Stratum Profiles for Status Offense Data       Counties reporting compatible data       Number of counties   Stratum County population ages 10–17 Counties in stratum Case-level Court-level Total Percentage of juvenile population 1 Fewer than 12,575 2,595 1,600 272 1,872    72% 2 12,575–53,250    353    188   39    227 66 3 53,251–133,700    104      52     8     60 62 4 More than 133,700      32     23     6     29 94 Total   3,084 1,863 325 2,188 73

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 2002, case-level data describing 1,047,793 delinquency cases handled by 1,884 jurisdictions in 35 states met the Archive’s criteria for inclusion in the development of national estimates. Compatible data were available from Alabama, Alaska, Arizona, Arkansas, California, Connecticut, District of Columbia, Florida, Georgia, Hawaii, Illinois, Indiana, Kentucky, Maryland, Minnesota, Mississippi, Missouri, Montana, Nebraska, Nevada, New Jersey, New Mexico, North Dakota, Ohio, Oklahoma, Pennsylvania, South Carolina, South Dakota, Tennessee, Texas, Utah, Virginia, Washington, West Virginia, and Wisconsin. These courts had jurisdiction over 66% of the nation’s juvenile population in 2002. Compatible courtlevel aggregate statistics on an additional 69,633 delinquency cases from 227 jurisdictions were reported from the states of California, Idaho, Illinois, Indiana, New York, and Vermont. In all, the Archive received compatible case-level data and court-level statistics on delinquency cases from 2,110 jurisdictions containing 75% of the Nation’s juvenile population in 2002 (table A–1).

Case-level data describing 101,812 formally handled status offense cases from 1,863 jurisdictions in 34 states met the criteria for inclusion in the sample for 2002. The contributing states were Alabama, Alaska, Arizona, Arkansas, California, Connecticut, District of Columbia, Florida, Georgia, Hawaii, Illinois, Indiana, Kentucky, Maryland, Minnesota, Mississippi, Missouri, Montana, Nebraska, Nevada, New Mexico, North Dakota, Ohio, Oklahoma, Pennsylvania, South Carolina, South Dakota, Tennessee, Texas, Utah, Virginia, Washington, West Virginia, and Wisconsin. These courts had jurisdiction over 63% of the juvenile population. An additional 325 jurisdictions in 6 states (California, Idaho, Indiana, Iowa, New York, and Vermont) reported compatible court-level aggregate statistics on 14,665 petitioned status offense cases. Altogether, compatible case-level and court-level data on petitioned status offense cases were available from 2,188 jurisdictions containing 73% of the U.S. juvenile population in 2002 (table A–2). Additionally, petitioned status offense case profiles in the Report include case-level data describing 1,146,308 cases and courtlevel aggregate data describing 114,527 cases for the years 1985 through 2001.

A list of states contributing case-level data (either delinquency or petitioned status offense data), the variables each reports, and the percentage of cases containing each variable are presented in Table A–3.

Table A–3: Content of Case-Level Data Sources, 2002 Data source Age at referral Gender Race Referral source Referral reason Secure detention Manner of handling Adjudication Disposition Alabama AL AL AL – AL AL AL AL AL Alaska AK AK AK AK AK AK AK AK AK Arizona AZ AZ AZ AZ AZ AZ AZ AZ AZ Arkansas AR AR AR – AR – AR AR AR California CA CA CA CA CA CA CA CA CA Connecticut CT CT CT CT CT – CT CT CT District of Columbia DC DC DC DC DC – DC DC DC Florida FL FL FL – FL – FL FL FL Georgia GA GA GA GA GA – GA GA GA Hawaii HI HI – HI HI – HI HI HI Illinois1 IL IL – IL IL IL IL IL IL Indiana2 IN IN IN IN IN IN IN IN IN Kentucky KY KY KY – KY – KY – – Maryland MD MD MD MD MD – MD MD MD Minnesota MN MN MN MN MN – MN MN MN Mississippi MS MS MS MS MS – MS MS MS Missouri MO MO MO MO MO MO MO MO MO Montana MT MT MT MT MT – MT MT MT Nebraska NE NE NE NE NE NE NE NE NE Nevada NV NV NV – NV NV NV NV NV New Jersey NJ NJ NJ – NJ – NJ NJ NJ New Mexico NM NM NM NM NM NM NM NM NM North Dakota ND ND ND – ND – ND ND ND Ohio3 OH OH OH – OH OH OH OH OH Oklahoma OK OK OK OK OK OK OK OK OK Pennsylvania PA PA PA PA PA – PA PA PA South Carolina SC SC SC SC SC SC SC SC SC South Dakota SD SD SD – SD SD SD SD SD Tennessee TN TN TN TN TN – TN TN TN Texas TX TX TX TX TX – TX TX TX Utah UT UT UT UT UT – UT UT UT Virginia VA VA VA VA VA VA VA – VA Washington WA WA WA WA WA – WA WA WA West Virginia WV WV WV WV WV WV WV – WV Wisconsin WI WI WI – WI – WI WI WI Percentage of estimation sample 99% 100% 95% 69% 97% 38% 100% 92% 96% Note: The symbol “–” indicates that compatible data for this variable are not reported by this state. 1 Data from Cook County only. 2 Data from Marion County only. 3 Data from Cuyahoga County only.

Juvenile Population

The volume and characteristics of juvenile court caseloads are partly a function of the size and demographic composition of a jurisdiction's population. Therefore, a critical element in the Archive's development of national estimates is the population of youth that generate the juvenile court referrals in each jurisdiction—i.e., the “juvenile” population of every U.S. county.

A survey of the Archive's case-level data shows that very few delinquency or status offense cases involve youth younger than 10. Therefore, the lower age limit of the juvenile population is set at 10 years for all jurisdictions. On the other hand, the upper age limit varies by state. Every state defines an upper age limit for youth who will come under the jurisdiction of the juvenile court if they commit an illegal act. (See “upper age of jurisdiction” in the “Glossary of Terms” section.) Most states define this age to be 17 years, although some states have set the age at 15 or 16. States often enact exceptions to this simple age criterion (e.g., youthful offender legislation and concurrent jurisdiction or extended jurisdiction provisions). In general, however, juvenile courts have responsibility for all law violations committed by youth at or below the upper age of original jurisdiction.

For the purposes of this Report, therefore, the juvenile population is defined as the number of youth living in a jurisdiction who are at least 10 years old but who are not older than the upper age of original juvenile court jurisdiction. For example, in New York, where the upper age of juvenile court jurisdiction is 15, the juvenile population is the number of youth residing in a county who are between the ages of 10 and 15.

The juvenile population estimates used in this Report were developed with data from the Census Bureau.¹ The estimates, separated into singleyear age groups, reflect the number of whites, blacks, and individuals of other races² who reside in each county in the Nation and who are between the ages of 10 and the upper age of original juvenile court jurisdiction.

Estimation Procedure

National estimates are developed by using the national case-level database, the national court-level database, and the Archive’s juvenile population estimates for every U.S. county. “County” was selected as the unit of aggregation because (1) most juvenile court jurisdictions in the United States are concurrent with county boundaries, (2) most data contributed by juvenile courts include the county in which the case was handled, and (3) youth population estimates can be developed at the county level.³

The Archive’s national estimates are generated by analyzing the data obtained from its nonprobability sample of juvenile courts and then weighting those cases to represent the number of cases handled by juvenile courts nationwide. The Archive employs an elaborate multivariate weighting procedure that adjusts for a number of factors related to juvenile court caseloads: the court’s jurisdictional responsibilities (upper age); the size and demographic composition of the community; and the age, gender, and race profile of the youth involved in juvenile court cases.

The basic assumption underlying the estimation procedure is that similar legal and demographic factors shape the volume and characteristics of cases in reporting and nonreporting counties of comparable size and features. The estimation procedure develops independent estimates for the number of petitioned delinquency cases and the number of nonpetitioned delinquency cases handled by juvenile courts nationwide. Identical procedures are used to develop all case estimates.

The first step in the estimation procedure is to place all U.S. counties into one of four strata based on the population of youth between the ages of 10 and 17. The lower and upper population limits of the four strata are defined each year so that each stratum contains one-quarter of the national population of youth between the ages of 10 and 17. In each of the four strata, the Archive determines the number of juveniles in three age groups: 10- through 15-year-olds, 16-year-olds, and 17-year-olds. The three age groups are further subdivided into three racial groups: white, black, and other. Thus, juvenile population estimates are developed for nine age-byrace categories in each stratum of counties.

The next step is to identify within each stratum the jurisdictions that contributed to the Archive case-level data consistent with JCS reporting requirements. The national case-level database is summarized to determine within each stratum the number of court cases that involved youth in each of the nine age/race population groups. Case rates (number of cases per 1,000 juveniles in the population) are developed for the nine age/race groups within each of the four strata.

For example, assume that a total of 2,870,000 white youth between the ages of 10 and 15 resided in the stratum 2 counties that reported case-level data to the Archive. If the Archive’s case-level database shows that the juvenile courts in these counties handled 50,523 petitioned delinquency cases involving white youth between the ages of 10 and 15, the number of cases per 1,000 white youth ages 10 to 15 for stratum 2 would be 17.6, or:

(50,523/2,870,000) x 1,000 = 17.6

Comparable analyses are then used to establish the stratum 2 case rates for black youth and youth of other races in the same age group (50.7 and 16.2, respectively).

Next, information contained in the national court-level database is introduced, and case rates are adjusted accordingly. First, each court-level statistic is disaggregated into the nine age/race groups. This separation is accomplished by assuming that, for each jurisdiction, the relationships among the stratum’s nine age/race case rates (developed from the caselevel data) are paralleled in the aggregate statistic.

For example, assume that a jurisdiction in stratum 2 with an upper age of 15 processed 600 cases during the year and that this jurisdiction had a juvenile population of 12,000 white youth, 5,000 black youth, and 2,000 youth of other races. The stratum 2 case rates for each racial group in the 10–15 age group would be multiplied by the corresponding population to develop estimates of the proportion of the court’s caseload that came from each age/race group, as follows:

White:
(17.6 x 12,000) / [(17.6 x 12,000) + (50.7 x 5,000) + (16.2 x 2,000)] = 0.42

Black:
(50.7 x 5,000) / [(17.6 x 12,000) + (50.7 x 5,000) + (16.2 x 2,000)] = 0.51

Other:
(16.2 x 2,000) / [(17.6 x 12,000) + (50.7 x 5,000) + (16.2 x 2,000)] = 0.07

The jurisdiction’s total caseload of 600 would then be allocated based on these proportions. In this example, 42% of all cases reported in the jurisdiction’s aggregate statistics involved white youth, 51% involved black youth, and the remaining 7% involved youth of other races. When these proportions are applied to a reported aggregate statistic of 600 cases, this jurisdiction is estimated to have handled 252 cases involving white youth, 306 cases involving black youth, and 42 cases involving youth of other races age 15 or younger. The same method is used to develop case counts for all nine age/race groups for each jurisdiction reporting only aggregate court-level statistics.

The disaggregated court-level counts are added to the counts developed from case-level data to produce an estimate of the number of cases involving each of the nine age/race groups handled by reporting courts in each of the four strata. The juvenile population figures for the entire sample are also compiled. Together, the case counts and the juvenile population figures are used to generate a revised set of case rates for each of the nine age/race groups within the four strata.

Stratum estimates for the total number of cases involving each age/race group are then calculated by multiplying the revised case rate for each of the nine age/race groups in a stratum by the corresponding juvenile population in all counties belonging to that stratum (both reporting and nonreporting).

After the national estimate for the total number of cases in each age/race group in each stratum has been calculated, the next step is to generate estimates of their case characteristics. This estimate is accomplished by weighting the individual case-level records stored in the Archive’s national case-level database. For example, assume that the Archive generates an estimate of 41,254 petitioned delinquency cases involving white 16-year-olds from stratum 2 counties. Assume also that the national case-level database for that year contained 25,758 petitioned delinquency cases involving white 16- year-olds from stratum 2 counties. In the Archive’s national estimation database, each stratum 2 petitioned delinquency case that involved a white 16-year-old would be weighted by 1.60, because:

41,254/25,758 = 1.60

The final step in the estimation procedure is to impute missing data on individual case records. Table A–3 indicates the standardized data elements that were available from each jurisdiction’s 2002 data set. The procedures to adjust for missing data assume that case records with missing data are similar in structure to those without missing data. For example, assume that among cases from a particular stratum, detention information was missing on 100 cases involving 16-year-old white males who were petitioned to court, adjudicated for a property offense, and then placed on probation. If similar cases from the same stratum showed that 20% of these cases involved detention, then it would be assumed that 20% of the 100 cases missing detention information also involved detention. Thus, missing data are imputed within each stratum by reviewing the characteristics of cases with similar case attributes (i.e., the age, gender, and race of the youth; the offense charged; and the court’s decisions on detention, petition, adjudication, and disposition).

More detailed information about the Archive’s national estimation methodology is available on request from the National Center for Juvenile Justice.