The Career History Archival Medical and Personnel System is a database that provides information on cancer, chronic diseases, occupational and preventive medicine, epidemiological research, and the use of health care in the Navy and Marine Corps. It was created at the Naval Health Research Center for enlisted Navy personnel, and it is being expanded to encompass all military personnel. Its objective is to provide a comprehensive, chronologically ordered database of career and medical events in all active duty military service members and to track career and disease events in order from the date of entry to service to the date service ended. Events include the dates of beginning and ending of each specific military occupation, all assignments to a military units or ships, all hospitalized diseases, and other events. The database contains detailed epidemiological data on more than six million members of the military services. It is the largest known epidemiological database in the United States.

This article describes the design and uses of the Career History Archival Medical and Personnel System (CHAMPS), a comprehensive database of career and medical information on all individuals who have served on active duty in the Navy and Marine Corps, and, in more recent years, all Department of Defense (DoD) services.1 The database covers the period from January 1, 1965 to the present for enlisted Navy service members. For all other services, medical events and denominator data are available from 1988 to the present. This report describes use of the database for epidemiological research on health and performance in the military.

CHAMPS was developed and is maintained by the Naval Health Research Center (NHRC) in San Diego, California. The CHAMPS system compiles highly detailed career and medical histories on individuals in the military from a variety of sources. Records are arranged for each individual as events in chronological order, and a set of event records for an individual provides a logical and comprehensive history from his/her time of enlistment to his/her time of ending service. Each event record contains variables that reflect the type and date of the event and the member’s status at the time of the event. There are two categories of event records: career and medical.

Career data for Navy and Marine Corps service members were compiled from Bureau of Naval Personnel and Marine Corps Headquarters electronic files. Medical records for enlisted Navy members were compiled from hospitalization records from military hospitals, medical board findings, physical evaluation board findings, and death records. All data were edited for accuracy and consistency before being entered into CHAMPS. All social security numbers (SSNs) were verified, and numbers that could not be verified were corrected, using name and birth date as alternate identifiers. All changes in content or coding were documented in a cumulative electronic documentation file. As new files for the Army, Air Force, and Coast Guard are made available, they are being integrated into CHAMPS. CHAMPS tracks cross-service changes, such as from Navy to Air Force, and changes from enlisted to officer status.

The first event in CHAMPS histories is the accession event record for the individual. Variables in the accession event record include term (length) of enlistment, whether the member is on regular or reserve status, pay grade or rank, primary and secondary military occupations, education, age, type of enlistment, and branch and component where the member served in the past, if the individual had previous military service. The career data in the accession event record provide a comprehensive description of the characteristics of the incoming recruit. The career data include data obtained from recruits during their health and mental status examinations during military entry processing at Military Entry Processing Stations throughout the United States. Subsequent records describe events in the individual’s career as they occur.

Event records are created for changes in occupation, duty station, pay grade, name, SSN, unauthorized absences, desertions, and discharges. The values for commonly used variables, such as age, pay grade, occupation, duty station, marital status, dependents, and length of service, are current for the event date. The most important variables recorded as events are primary occupation (rate); secondary occupation; duty station activity (type of ship or duty station); home port or base zip code; name and previous names if any; SSN, previous SSNs, and current verified SSN; date of loss from military service; and DoD manpower separation code.

Another series of event records describe all hospitalizations and certain other medical events. Variables in the hospitalization record include all discharge diagnoses (up to eight per hospitalization), number of diagnoses (from 1 to 8), dates admitted and discharged, number of days hospitalized, type of release, military theater of operation, pay grade, occupational specialty, and cause, when the hospitalization is a result of an accident, poisoning, or violence. Other medical records are also included when available, such as results of medical and physical evaluation boards, death, human immunodeficiency virus (HIV) testing and serological status, existence of a condition before enlistment, and identification of the hospital. Data elements that vary over time, such as age, pay grade, and occupation, are obtained from personnel records because demographic and current status data contained in medical records are often inaccurate. Age at event, for example, is computed by subtracting the birth date from the date of the event.