It is critical to know how ASVAB scores are calculated and what they are used for. The Armed Services Vocational Aptitude Battery (ASVAB) tests are used to identify whether a candidate is qualified to enlist in a particular branch of the U.S. Military. The ASVAB test is also used to determine which military jobs (referred to as MOS for Military Occupational Specialties) a candidate is best suited for. ASVAB scores can also be used by test takers to help explore which careers they may be a good fit for them – whether they go into the military or not. While no one officially passes or fails the ASVAB, each branch of the military has specific minimum scores required for enlistment. Your scores also affect the type of military job, enlistment bonuses and salary you are eligible for.
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).