A test developer compares a student's performance on a newly developed math achievement test to the same student's performance on a well established math achievement test for the purpose of exploring the ________ validity of the new test.

Test Validity and Reliability is known as the degree in which a test or other measuring device are truly measuring what is intended to measure. The test question “1 + 1 = ___2__” is a valid basic addition question that truly measures a student’s ability to perform basic addition. In many cases it becomes less valid as a measurement of advanced addition because as it put emphasis on some required knowledge for addition, it does not represent all of knowledge required for an advanced understanding of addition. On a test designed to measure knowledge of American History, this question becomes completely invalid. The ability to add two single digits has nothing do with history.