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.
The General Science section of the test covers earth, space, and physical and life sciences. Because science is such a vast and dynamic topic, focus your study on basic principles. This gives you a good foundation to work through any question that is asked of you. Typical questions may include: “Why is air less dense than water?” or “How do you convert Celsius temperature to Fahrenheit?” The CAT-ASVAB test asks 16 questions in 8 minutes, while the pencil-and-paper version asks 25 questions in 11 minutes.
The ASVAB test is administered to potential military recruits to help determine which branch of service and which military jobs they will be best suited for. It is not a test of intelligence and is administered only in English. The test consists of nine subjects: General Science, Arithmetic Reasoning, Word Knowledge, Paragraph Comprehension, Mathematics Knowledge, Electronics Information, Auto and Shop Information, Mechanical Comprehension, and Assembling Objects.