You are tested in four critical areas — Arithmetic Reasoning, Word Knowledge, Paragraph Comprehension and Mathematics Knowledge (see below) — these scores count towards your Armed Forces Qualifying Test (AFQT) score. The AFQT score determines whether you’re qualified to enlist in the U.S. military. Your scores in the other areas of the ASVAB determine how qualified you are for certain military specialties. Score high, and your chances of getting the specialty/job you want increase. The better score you get, the better chance you have of pursuing the specialty or field that you desire.
The projected active duty end strength in the armed forces for fiscal year 2017 was 1,281,900 servicemembers, with an additional 801,200 people in the seven reserve components. It is an all-volunteer military, but conscription through the Selective Service System can be enacted at the President's request and Congress' approval. All males ages 18 through 25 who are living in the United States are required to register with the Selective Service for a potential future draft.
As a general rule of thumb, anything over an 85 on the ASVAB will qualify you for nearly any position in the armed forces. But there are slight breakdowns within each score. For example, in order to qualify for Surveillance and Communications (SC) in the Army, Word Knowledge, Paragraph Comprehension, Arithmetic Reasoning, Auto & Shop and Mechanical Comprehension all require high marks. Though scoring an 85 or above would guarantee you scored in a high enough percentile to qualify for SC.
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.
Obviously, the most important way to prepare to take the test is to spend plenty of time reviewing practice test questions. Look at questions from all sections of the test, but pay special attention to questions on the Word Knowledge, Paragraph Comprehension, Arithmetic Reasoning, and Mathematics Knowledge sections, which will be used to calculate your Armed Forces Qualification Test (AFQT) score for enlistment.
All test takers are given a summary results sheet that shows their percentile score in every test area. A percentile score of 50 means that a score was achieved that was better than 50 percent of all test takers. Percentile scores are given specifically for test takers of their gender and their grade level. Information obtained from the test is only shared with agencies within the Department of Defense. Test takers are informed that their specific scores will be used for up to two years for recruiting purposes. After two years, test scores will be used for research purposes only.