Research for Armed Services Vocational Aptitude Battery

Within a few years the Department of Defense may begin administering the Armed Services Vocational Aptitude Battery (ASVAB) using Computerized Adaptive Testing (CAT). In CAT, each test item is characterized by an Item Response Curve (IRC), which describes how the probability of correctly answering the item increases with ability. A recent study conducted by the Center for Naval Analyses found that IRCs of many items in the experimental CAT item pool for the ASVAB changed substantially from paper-pencil to CAT administration. This research memorandum examines the effects of these changes on scores of individual examinees.

The Armed Services Vocational Aptitude Battery (ASVAB) is administered in high schools as part of the Defense Department's recruiting effort. Norms based on a national sample are currently available for grades 11 and 12 only. These were computed from data collected by the National Opinion Research Center (NORC) in 1980. Additional data from a nonrandom sample were collected in 1984 by the Military Entrance Processing Command (MEPCOM). The objectives of the present study were to examine the psychometric appropriateness of using the ASVAB in 9th and 10th grades and to develop norms for these grades. Analysis of appropriateness was based on conventional test and item statistics, and factor analysis. The use of ASVAB in 9th and 10th grades was found to be psychometrically appropriate. Ninth and 10th grade norms were developed by transforming MEPCOM cumulative percentages into national percentile scores. Transformation curves were obtained by combining information from MEPCOM and NORC samples in grades 11 and 12. The average transformation was then used in 9th and 10th grades to convert MEPCOM cumulative percentages into national percentile scores.

This paper evaluates seventeen ASVAB composites that were proposed as alternatives to replace the current AFQT. The alternatives are evaluated primarily on the basis of their predictive validity and their effects on the applicant pool.

Data is presented showing that results on high school ASVAB speeded subtests are inconsistent with results on nonspeeded subtests. Causes for the inconsistencies are explored, and corrective actions based on these findings are recommended.