Final answer:
If Paul receives different results every time he completes the online personality test, then the test lacks test-retest reliability, which is the test's ability to consistently produce the same results over time.
Step-by-step explanation:
If Paul's complaint about the online personality test is accurate, and it gives him a different profile every time he completes it, then the test lacks test-retest reliability. Test-retest reliability refers to a test's ability to yield consistent results over multiple administrations under the same circumstances. This form of reliability is crucial for psychological assessments such as the MMPI-2-RF as it ensures that the outcomes are stable over time. In contrast, internal consistency measures if different items aiming to assess the same general construct produce similar results, inter-rater reliability assesses the degree of agreement among different raters, and face validity refers to whether a test appears to measure what it is supposed to measure at face value, without necessarily proving that it does indeed do so.
In the case described by Beutler, Nussbaum, and Meredith (1988), where the MMPI was administered to police officers at different intervals, changes in scores reflecting vulnerability to certain conditions were likely due to actual changes in the subject's condition over time rather than inconsistencies in the test. However, if the MMPI or any other psychological test produced significantly different outcomes for an individual without any intervening variable or change in condition, it would suggest poor test-retest reliability.