ABSTRACT
The most important characteristic of a test is validity. Validity answers the question, Does a test actually measure what we think it is measuring? Although validity is one of the most important concepts in the field of measurement, there is no one single way to look at it. This chapter examines content-related evidence of validity as a general concept. It looks at three specific types of content-related evidence of validity: instructional validity, curricular validity, and face validity. Content-related evidence of validity is extremely important for classroom tests, although there is no way to mathematically estimate content validity. Validity is the most important characteristic of a measurement device. The different types of validity are not equally important for different measurement devices. Classroom tests should stress content-related evidence of validity. There should be a very close match between the items on the test and the material that was taught.
