Diagnosis does not necessarily mean prescription unless the data collected have demonstrated high reliability and validity. Teachers tend to use tests that they prepared themselves much more often than any other type of test to monitor what has been previously learned. Systematic observations of a student applying a skill can be thought of as a form of performance testing. Testing used in these ways are a prerequisite for determining how quickly new material can be presented. These tests help the teacher gain a perspective of the range of attained learning as well as individual competence.
Many factors enter into the important decision of moving a student into the next grade.
Intuition is an important part of any decision but that intuition is enhanced when coupled with data. Standardized tests, and records of classroom performance on less formal tests are essential for supplying much of the data upon which these decisions are based. Classroom instruction depends upon a large support network. That network needs information if an adequate support level is to be maintained. Tests in various forms can supply that information.