# 1.59

(1 pts.) Ralph has been sad and listless for 3 years. He can't sleep and has lost his appetite. Using a diagnostic system, one clinician arrives at a diagnosis of depression. Using the exact same diagnostic system, another clinician arrives at a diagnosis of schizophrenia. What is the problem with this system?

A) It lacks construct validity.
B) It lacks universality.
C) It lacks reliability.
D) It lacks criterion validity.

(MY answer IS C)

I agree.

I would agree with D.

• Construct Validity - Words like assertiveness, giftedness, and hyperactivity refer to abstract ideas that humans construct in their minds to help them explain observed patterns or differences in the behavior of themselves or other people. Intelligence, self-esteem, aggressiveness, and achievement motivation, creativity, critical thinking ability, reading comprehension, mathematical reasoning ability, shyness, curiosity, hypocrisy, and procrastination are also examples of constructs. A construct is an unobservable, postulated attribute of individuals created in our minds to help explain or theorize about human behavior. Since constructs do not exist outside the human mind, they are not directly measurable. In other words, the degree to which one can infer certain constructs in a psychological theory from the test scores.

In the future, you can find the information you desire more quickly, if you use appropriate key words (like the alternatives) to do your own search. Also see http://hanlib.sou.edu/searchtools/.

a. it lacks construct validity

To determine the problem with the diagnostic system, we need to understand the different possibilities mentioned in the options:

A) Construct validity refers to the extent to which a measurement tool accurately measures the construct or concept it is intended to measure. This option suggests that the diagnostic system may not accurately capture the construct of depression or schizophrenia. However, it does not address the issue of consistency in diagnosis.

B) Universality refers to the generalizability of a diagnostic system across diverse populations. This option suggests that the diagnostic system may not be applicable to all individuals. However, it does not explain why two clinicians arrive at different diagnoses using the same system.

C) Reliability refers to the consistency or stability of measurements or observations. In this context, it means that the diagnostic system should produce consistent diagnoses for the same individual over time and across different clinicians. This option suggests that the diagnostic system lacks reliability because two clinicians using the same system arrive at different diagnoses for Ralph.

D) Criterion validity refers to the extent to which a measurement tool accurately predicts a specific criterion or outcome. In this case, it means that the diagnostic system should accurately predict the presence or absence of depression or schizophrenia. This option does not address the issue of consistency in diagnosis.

Given the information provided, it seems that the most appropriate answer is C) It lacks reliability. The fact that two clinicians using the same diagnostic system arrive at different diagnoses for Ralph indicates a lack of consistency in the system's outcomes.