To some, this includes both the education students have received and by extension the quality of education the school provides. The reasoning is then extended to conclude that a school with high test scores should receive high marks from accreditors and a school whose students have low test scores should receive low marks. The presumption here is that a student who achieves high test scores is well educated and the school is responsible. A test is a sampling of what one knows and can do within defined parameters.
Considerable research has to be done to ensure that tests are valid and reliable.
The reliability and validity scores are, or should be, available for all widely used standardized tests. In other words, tests, like lie detectors, are not infallible. One can, however, be reasonably confident in a test that has demonstrated high reliability and validity scores. Even if a test is found highly valid for what it purports to test, it may not be valid for testing what is taught in a particular school or class. It is only valid if what is taught is what it purports to test.