Dr Sheffield Is a Clinical Psychologist Who Specializes in Treating

Dr. Sheffield is a clinical psychologist who specializes in treating pathological gambling. Pathological gambling is defined as being unable to resist impulses to gamble. Bothered by not having a good measure that he can give to clients to determine whether they are suffering from this condition, he creates a new measure of pathological gambling. The measure has 15 questions, and it takes 20 minutes to complete.
Dr) Sheffield has decided to test the discriminant validity of his new measure. He has a group of first-time Gamblers Anonymous (GA) attendants complete his measure and finds that they score higher than a group of people who do not attend the group. Which of the following results would provide evidence for discriminant validity?

A) He finds that the GA attendees score higher on his measure than the non-GA attendees.
B) He finds that the measure of gambling is not correlated with a measure of life satisfaction in the same two groups of people.
C) He finds that more recent GA joiners score higher than veteran GA attendees, who are more recovered.
D) He finds that the measure he used is also associated with people's past diagnoses of pathological gambling.