Assessment, Statistics, and Research

  What makes a test valid? is a tricky question.  The short, and rather obnoxious response is, “nothing.”  Like reliability , validity is a property of test scores  rather than tests but more accurately, an interpretation of the scores. But it is important to take the question seriously when test-takers and users are wondering how much confidence to place in a test score. As with many aspects of science, the answers can be simply stated but there is a complicated backstory. Validity Traditions For many, the traditional views of test score validity will be sufficient. Tests measure constructs. Scientific constructs are ideas that have features that can be measured like reading comprehension, dominance, short-term memory, and verbal intelligence. Construct validity is not a single entity but rather the current state of knowledge about how a test instrument’s scores have functioned in many settings and in relation to criteria. Construct vali