Term referring to how well a test or experiment measures up to its claim. Construct validity is a device used almost exclusively in social sciences, psychology, and education.
How accurately a test measures a particular attribute, content validity face validity; concurrent validity.
In a research study, the fitness of a particular research method for the use to which the study is put or its suitability for the conceptual or theoretical use for which it is employed.
The degree to which a measurement accurately counts the objects it is intended to evaluate; the fitness of a test to its target or to the theory that it is intended to illuminate. Imagine that a researcher wants to determine how important spirituality is to survival in patients with cancer. She may design a test to measure spirituality. As a first approximation she decides to measure the number of times per month that her subjects attend religious services and to correlate that number with months of survival after the diagnosis of cancer. Now, suppose she finds that people who report themselves as attending church frequently do not survive cancer more than individuals who rarely attend church. There are at least two possible explanations for her findings: 1. spirituality is unrelated to cancer survival; or, 2. her test of spirituality did not have construct validity, i.e., the number of times a month that a person attends church may prove to be an inaccurate measure of religious faith.