Using the right ASVAB study guide is an important factor in determining how well you will do on the exam. Each branch of the U.S. Military requires you take an ASVAB (Armed Services Vocational Aptitude Battery) exam. Your scores on the ASVAB determine not only your entrance into the military, but also your job, advancement opportunities, and potential salary. The ASVAB exam consists of questions in ten different areas, but in general, the exam is measuring your aptitude in four key areas: Math, Verbal, Science and Technical, and Spatial. To efficiently prepare for your ASVAB exam, check out our recommended study guides, our free practice exams, our ASVAB flash cards, and our ASVAB study tips.
The IRT model underlying ASVAB scoring is the three-parameter logistic (3PL) model. The 3PL model represents the probability that an examinee at a given level of ability will respond correctly to an individual item with given characteristics. Specifically, the item characteristics represented in the 3PL model are difficulty, discrimination (i.e., how well the item discriminates among examinees of differing levels of ability), and guessing (i.e., the likelihood that a very low ability examinee would respond correctly simply by guessing).