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.  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.  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.
You can take the test as a junior or senior in high school and use the score to enlist, provided that you are at least 17 years old and took the test no earlier than 2 years before you begin enlistment processing. If you are at least 17, you can take the test at a Military Processing Station (MEP) or a satellite Military Entrance Test (MET) location.
These supply points are also used to provide military engineering services, such as the recovery of defective and derelict vehicles and weapons, maintenance of weapons in the field, the repair and field modification of weapons and equipment; and in peacetime, the life-extension programmes undertaken to allow continued use of equipment. One of the most important role of logistics is the supply of munitions as a primary type of consumable, their storage, and disposal.
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.
Reading page after page of boring content can cause the strongest minds to wander. Taking practice tests are a great way to break up the monotony of studying. Taking a practice test challenges you and keeps you interested in the material. Then you can review your test results and go over the questions you got wrong committing the right answer to memory. It’s a great, streamlined way to learn.
The majority of people who complete the exam have little intention of entering the military. However, it’s important to keep in mind that the United States military is actually one of the nation’s largest employers. If you’re undecided about your future after high school graduation, taking the test can give you a better picture of your options in both civilian and military life.
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.