There is a distinction that one learns about on the first day of a course in psychological research methods. It is the difference between internal and external validity. Internal validity is ...

From the perspective of score interpretation, the purpose of testing accommodations is to reduce the dependence of test scores on factors that are irrelevant to the construct that is being assessed.

In my previous blog post, I noted that reliability and validity are two essential properties of psychological measurement. Measures of intelligence, personality, vocational interests, and so forth ...