Based upon the norms of a large population. It is best used to verify strengths and weaknesses of a program and to justify what is being done.
Tests that have been developed through use on large groups, with the resulting scores being used to establish norms for students of specific ages or grades, their main purpose to establish a comparison between a particular student’s performance and the average performance of others. For example, if most students in the fourth grade score 75 on a particular achievement test, the norm for fourth-graders is 75. If a third-grader later takes the test and scores 75, her score is better than the average for her grade, and she is said to have an educational age of fourth grade, a comparison called a grade-equivalent. Most widely used, numerically scored tests, such as achievement tests, are developed and standardized on large populations, and the scores tend to be distributed evenly along a normal distribution or bell curve, like an upturned tulip¬ shaped bowl, with most scores falling in the middle and many fewer scores at the top and bottom ranges. Such tests generally have written instructions for use. Among professionals, standardized tests are often evaluated on the basis of their reliability (consistency) and validity (accuracy in measuring what is intended).
A test that has been developed empirically, has adequate norms, definite instructions for administration, and evidence of reliability and validity.