The test measures competency in 9 different subjects, which include General Science, Electronics Information, Auto and Shop Information, Mechanical Comprehension, Assembling Objects, Word Knowledge, Paragraph Comprehension, Arithmetic Reasoning, and Mathematics Knowledge. These last four sections- Word Knowledge, Paragraph Comprehension, Arithmetic Reasoning, and Mathematics Knowledge are the most important, as they make up something called the AFQT (Armed Forces Qualifications Test). An applicant’s AFQT score is what determines whether or not they are able to serve in the military at all, as each branch has minimum scores for enlistment.
The Armed Forces Qualification Test (AFQT) is used by all of the Services to determine if an applicant is eligible for the military. Four of the ASVAB subtests are combined to form the AFQT. It measures general cognitive ability and is composed of verbal and mathematics subtests. AFQT scores are grouped into categories for reporting purposes. The table below shows the AFQT categories and the percentile score ranges corresponding to the categories. Applicants that score in AFQT category IIIA or higher may qualify for enlistment incentives.
One ASVAB sub-measure, the Armed Forces Qualification Test (AFQT)--which is just a separate analysis of the same tests that focuses only on four of the subtests--is also population-referenced, but its score from 1-99 is a percentile score. This means that if you score a 73, you scored as well as or higher than 73% of test-takers in the national sample.