After a candidate has completed the ASVAB they must wait one calendar month before retaking the exam. An additional calendar month must pass before retesting a second time. Six calendar months must pass before retaking the test a third time. The scores received from the ASVAB may be used for enlistment for up to two years from the initial test date. 
The Mechanical Comprehension section of the ASVAB practice test measures your understanding of basic mechanical principles and mechanisms. You may be asked why an intake valve on a pump opens when the piston goes down, or what direction friction is going when shown a diagram of a skier. The CAT-ASVAB has 16 questions in 20 minutes; the paper-and-pencil version has 25 questions in 19 minutes.
The underlying model used for the ASVAB is a three-parameter logistic (3PL) model. This model represents the probability that an examinee at a given level of ability will respond correctly to an individual item with given characteristics. The characteristics used are difficulty, discrimination and guessing (this refers to the likelihood that a very low ability examinee would respond correctly simply by guessing).

The Electronics Information section of the practice test gauges your knowledge of electrical equipment and parts, including circuits, currents, batteries, and resistors. An example may be, “Because solid state diodes have no filament, they: don’t work, are less efficient than tubes, require less operating power, or require more operating power?” The CAT-ASVAB has 16 questions in 8 minutes; the paper-and-pencil version has 20 questions in 9 minutes.
Commander-in-chief: President of the United States Secretary of Defense Deputy Secretary of Defense Secretary of Homeland Security Deputy Secretary of Homeland Security Joint Chiefs of Staff: Chairman Vice Chairman United States Congress: Committees on Armed Services: Senate House Active duty four-star officers United States military seniority National Security Act of 1947 Goldwater–Nichols Act
The Armed Services Vocational Aptitude Battery (ASVAB) is a comprehensive test that helps determine students’ eligibility and suitability for careers in the military. Students who score in the 31st percentile are eligible for a wide variety of careers (combined with standards such as physical condition and personal conduct). Students and schools are also encouraged to take advantage of a free career exploration program that links personal interests with demonstrated aptitudes from the 9 ASVAB subtests, half of which relate to vocational skills, in addition to math and verbal skills.
Achieving the minimum required AFQT score established by an individual branch gets your foot in the door, but the higher you score, the better. For example, if you need a medical or criminal history waiver in order to enlist, the military personnel who make those decisions are more likely to take a chance on you if they think you’re a pretty smart cookie.

AFQT scores are the primary measure of recruit potential. Figure 2.7 indicates the percentage of NPS recruits who scored at or above the 50th percentile (Categories I–IIIA) since FY 1973. Numerical data are in Appendix D, Table D-12. The drop in Category I–IIIA recruits after FY 1976 was due primarily to the miscalibration of the ASVAB. [1] In FY 1976, when new versions of the ASVAB were introduced, an error in calibrating the score scales made the new versions "easier" than the old versions (i.e., applicants received test scores higher than their actual ability). In FY 1980, an independent study of the calibration was made and the test was correctly calibrated. Then, Congress added legal provisions stipulating that no more than 20 percent of accessions could be in Category IV and that such accessions had to be high school diploma graduates. [2] However, as previously stated, Defense Planning Guidance decreases this limit even further, allowing no more than 4 percent of recruits to come from Category IV.

The paper-and-pencil version of the test administered at a Mobile Examination Test (MET) site usually takes 3–4 hours. The time needed to take the CAT-ASVAB test can vary. The test is adaptive. If the candidates answer a question correctly, they are given one of increasing difficulty. If the candidates miss a question, they are subsequently given an easier item. This pattern continues until the test is finished. Because of its adaptive nature, the CAT-ASVAB test generally takes about half the time of the paper-and-pencil version.


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).

The paper-and-pencil version of the test administered at a Mobile Examination Test (MET) site usually takes 3–4 hours. The time needed to take the CAT-ASVAB test can vary. The test is adaptive. If the candidates answer a question correctly, they are given one of increasing difficulty. If the candidates miss a question, they are subsequently given an easier item. This pattern continues until the test is finished. Because of its adaptive nature, the CAT-ASVAB test generally takes about half the time of the paper-and-pencil version.


Each year, many high school and postsecondary students take the free Armed Services Vocational Aptitude battery (ASVAB).  The ASVAB is the most widely used multiple-aptitude test battery in the world.  It consists of eight tests that measure your skills and abilities in the following areas:  General Science; Arithmetic Reasoning; World Knowledge; Paragraph Comprehension; Mathematics Knowledge; Electronics Information; Auto and Shop Information; Mechanical Comprehension.
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.
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