The Concept of Reliability: Putting the "Psyche" into Psychometric

Reliability typically is regarded as a property of scales. If one’s scores are (in)consistent from time 1 to time 2, the test is assumed to be (un)reliable. However, an alternative conceptualization of reliability is that it is a property of persons and their responses; test scores are 'reliable' when a person responds to test items in a manner that is consistent, which implies that a test could be reliable for one person but not for another. Two studies were conducted to test the hypotheses that people who are schematic for a trait will provide more consistent responses both within test items (internal consistency) and across test sessions (retest reliability) than people who are aschematic for the trait. An internet study provided evidence partially supportive of the hypothesis; schematics displayed higher internal reliability than aschematics on two trait measures. In the second study, conducted in two waves in a psychology laboratory, although we obtained evidence for successfully measuring schemas, contrary to the retest hypothesis, there were no differences between schematic and aschematic alphas across the testing sessions.