Validity

integrated evaluative judgement of the degree to which empirical evidence and theoretical rationales support the adequacy and appropriateness of inferences and actions based on test scores or other modes of assessment (Moss).

When assessing the validity of a claim, it is wise to ask, "How could I be wrong?"

A test can be invalid if there is internal bias in the form of content selection and question selection and wording. For example, if students answer questions according to process of elimination or key-word linking, conceptual knowledge is not being assessed. Rather, testing skills is being assessed. An assumption that this test is assessing conceptual knowledge is therefore invalid.