From http://www.us.elsevier.com Psychological measurements: their uses and misuses (PDF)
“The words ‘test’ and ‘measurement,’ as used in psychology, are misleading because of the implied similarity to scientific measurements and medical tests. Conventional psychological testing is quite different from scientific measurements in the natural sciences.”
“There are no units of <psychological> measurement and no true zeros. Whatever psychological measurement is, it is not scientific measurement as defined in the natural sciences… This applies to the majority of psychological concepts and variables,” says Paul Kline, psychometric theorist.
“…it is often mistakenly believed that psychological tests are ‘objective’, meaning that their findings and scores reflect an outside existence (as opposed to being subjective) and are real or at least approximate something close to it…”
“The term <objectivity> in psychology refers to the standard ways in which <the tests> are administered, recorded and interpreted… Psychological tests, then, are not tests of mental structures or entities as are physical tests , neither are they objective in terms of real or physical existence – they are tests of psychological constructs…”
And yet, psychologists actively promote the false presentation of psychological concepts as belonging to scientific reality. We must ask, how many lives have been negatively impacted by this misrepresentation?
IT’S MAGIC, RELIGION, SOCIAL ENGINEERING, BUT NOT SCIENCE.