What measures the extent to which a test samples the behavior of interest?

Content validity refers to the degree to which a test accurately measures the specific behavior or construct it is intended to assess. This type of validity ensures that the test covers the full range of the topic and adequately reflects the specific area of interest. For instance, if a math test aims to evaluate a student’s understanding of algebra, it should include various algebraic concepts and types of problems. A test with strong content validity would include questions that represent all relevant aspects of algebra, ensuring that the assessment is comprehensive and relevant.

In contrast, construct validity is concerned with whether a test truly measures the theoretical construct it is intended to measure. Predictive validity refers to how well a test predicts future performance or outcomes, while external validity deals with the extent to which the findings from a study can be generalized to or have relevance for settings, people, or times other than the ones studied. These alternative types of validity do not specifically address the sampling of behavior required by the item in question.