What the fourth grade score for the adult means is that the adult reads very poorly relative to other adults who may score at the ninth, tenth, or twelfth grade levels on the test. While the grade level score is based on the performance of children in the school grades, the interpretation of the score should be based on the performance of adults on the test. For this reason, standardized tests such as the Tests of Adult Basic Education (TABE) or Adult Basic Learning Examination (ABLE) provide norms for adults in adult basic education programs and other settings that permit test users to interpret scores both in grade levels (grade-school referenced norms) and in relation to adult performance on the tests.

Identifying differences among readers. The major use of norm-referenced test scores is to identify differences among a group of people for some purpose. The norm-referenced tests indicate how people perform relative to the norming group. For instance, are they below or above the average of the norming group.

The most widely used standardized, basic skills (reading, mathematics) test that is normed on a nationally representative sample of young adults (18 to 23 years of age ) is the Armed Forces Qualification Test (AFQT). This test has been specially designed to permit the armed forces to rank order young adults from those very low to those very high in basic skills and to screen out the least skilled from military service. The U. S. Congress has passed a law prohibiting young adults who score below the tenth percentile on the AFQT from entering military service.

Adult education programs frequently use norm-referenced reading tests to identify those with reading scores below the fourth or fifth grade levels, those scoring between the fifth and ninth grade levels, and those scoring at or above the ninth grade level. These categories are frequently used to assign adults to different levels of reading instruction: basic or beginning reading, mid-level reading, and high school equivalency (General Educational Development - GED) education.

The use of standardized, norm-referenced tests for selection or placement is not an altogether accurate procedure, if for no other reason than the fact that no test is perfectly reliable. That is, because of the differences in people's psychological conditions from time to time, and variations in the physical conditions of testing (for example, it may be very cold, or too hot, or too noisy one day, and so forth), people do not usually score the same on tests from one time to the next.

Also, when multiple-choice tests are used that have been designed to discriminate among a wide-range of ability levels, the tests will contain some very easy items, some average difficulty items, and some very difficult items. The multiple-choice format permits guessing. These conditions mean that a person may score correctly on some items by chance alone on one day, but not the next. This produces artifacts that should be avoided in adult education program evaluation.