Question: Identify and explain two of the three categories of validity traditionally used by measurement specialists.

Expert answer

There are three categories of validity that measurement specialists use to judge how well a test measures what it is supposed to measure. They are content validity, criterion-related validity, and construct validity.

Content validity is a judgment of how well the content of a test represents the construct being measured. In order to have content validity, a test must cover all important aspects of the construct. For example, a math test would be invalid if it only contained questions about addition and subtraction but not geometry or algebra.

Criterion-related validity is a judgment of how well the scores on a test predict some other behavior or outcome that is important. There are two types of criterion-related validity: concurrent and predictive. Concurrent validity is when the criterion being predicted is measured at the same time as the test. For example, if we wanted to know how well a new math achievement test predicts students’ grades in math class, we would administer the test and measure students’ grades at the same time. Predictive validity is when the criterion being predicted is measured at a later time than the test. For example, if we wanted to know how well a new math achievement test predicts students’ grades in math class next semester, we would administer the test now and measure students’ grades next semester.

Construct validity is a judgment of how well a test measures a hypothetical construct. A hypothetical construct is something that cannot be directly observed but can only be inferred from observable behaviors. For example,