Gender and ethnicity based differential item functioning on the armed services vocational aptitude battery

Abstract

Utilising Item Response Theory (IRT) methodologies, the Armed Services Vocational Aptitude Battery (ASVAB) was examined for differential item functioning (DIF) on the basis of crossed gender and ethnicity variables. Both the Mantel‐Haenszel procedure and an IRT area‐based technique were utilised to assess the degree of uniform and non‐uniform DIF in a sample of ASVAB takers. Findings were mixed. At the item level, DIF fluctuated greatly. Numerous instances of DIF favouring the reference as well as the focal group were found. At the scale level, inconsistencies existed across the forms and versions. Tests varied in their tendency to be potentially biased against the focal group of interest and at times, performed contrary to expectations. Implications for the ASVAB as well as other g‐loaded selection instruments are considered.