The Armed Services Vocational Aptitude Battery (ASVAB) is administered annually to more than one million military applicants and high school students. ASVAB scores are used to determine enlistment eligibility, assign applicants to military occupational specialties, and aid students in career exploration. The ASVAB is administered as both a paper-and-pencil (P&P) test and a computerized adaptive test (CAT). CAT-ASVAB holds the distinction of being the first large-scale adaptive test battery to be administered in a high-stakes setting. Approximately two-thirds of military applicants
currently take CAT-ASVAB; long-term plans are to replace P&P-ASVAB with CAT-ASVAB at all test sites. Given CAT-ASVAB’s pedigree—approximately 20 years in development and 20 years in operational administration—much can be learned from revisiting some of the major highlights of CATASVAB history. This paper traces the progression of CAT-ASVAB through nine major phases of development including: research and evelopment of the CAT-ASVAB prototype, the initial development of psychometric procedures and item pools, initial and full-scale operational implementation, the introduction of new item pools, the introduction of Windows administration, the introduction of Internet administration, and research and development of the next generation CATASVAB. A background and history is provided for each phase, including discussions of major research and operational issues, innovative approaches and practices, and lessons learned.