Research for Armed Services Vocational Aptitude Battery

The Rand Corporation has developed a model that determines cost-effective enlistment standards for Military Occupational Specialties. Since this model may have an impact on enlistment policy, it is important that the modeling approach used to determine the enlistment standards be fully understood. This research memorandum describes the modeling technique used by the Rand Corporation and compares the Rand approach to alternative modeling methods in an attempt to determine the sensitivity of the model outcome to the methodology employed.

The Armed Services Vocational Aptitude Battery (ASVAB) is administered in high schools and postsecondary schools as part of the Defense Department's Student Testing Program. Unit 1986, high school norms based on a national sample, were available for grades 11 and 12 only. These were computed from data collected in 1980 as a part of the Profile of American Youth (PAY) study. Additional data from a nonrandom sample were collected in 1984 by the Military Entrance Processing Command (MEPCOM). The objective of the present study was to develop norms for 10th grade. Tenth grade norms were developed by transforming MEPCOM cumulative percentages into national percentile scores. Transformation curves were obtained by combining information from MEPCOM and PAY samples in grades 11 and 12. The average transformation was then used in 10th grade to convert MEPCOM cumulative percentages into national percentile scores.

The selection of test content and the construction of job performance tests has not followed any specific methodology. For determining qualification standards on the Armed Services Vocational Aptitude Battery (ASVAB), a more absolute interpretation is required of the performance test scores. This report proposes that a domain-referenced approach is necessary for the linkage of job performance and aptitude in determining standards on the ASVAB. This absolute interpretation of test scores, called competency-based measurement, is based upon two critical requirements of the test construction process: detailed specification of the job requirements domain and appropriate sampling of test content from that domain.

The Numerical Operation (NO) subtest, used in the Armed Forces Qualification Test (AFQT), has a history of causing problems for the Armed Services Vocational Aptitude Battery (ASVAB) score scale. Two adjustments to the ASVAB score scale have been required since NO was made part of the AFQT in 1980. The purpose of this report is to present evidence that the NO subtest should be deleted from the AFQT and be replaced by the Math Knowledge (MK) subtest. Data are presented showing that the AFQT scores in 1984 were inflated by approximately three percentile score points.