Clinical depression is one of the most common chronic disorders in the U.S. When detected, it can be treated with psychotherapy or medications. The US Preventive Services Task Force recommends that primary care practitioners screen for depression when follow-up services are available. Investigators used data from the Hispanic Health and Nutrition Survey2 to test whether a brief measure of depressive symptoms, the Center for Epidemiologic Studies Depression Scale (CES-D) could be used to screen people for clinical depression. They used the Diagnostic Interview Schedule (DIS) as the gold standard and obtained the results below.

	Diagnostic Test/Gold Standard - Diagnostic Interview Schedule (DIS)
	Depression	No depression	Total
CES-D (+)	64	300	364
CES-D (-)	2	834	836
Total	66	1134	1,200

²Based on partial findings from Cho MJ, Mocicki EK, Narrow WE, Rae DS, Locke BZ, Regier DA. Concordance between two measures of depression in the Hispanic Health and Nutrition Examination Survey. Social Psychiatry and Psychiatric Epidemiology 1993;28:156-163.

1. What is the sensitivity? Express as a percentage.

Group of answer choices

• 97%
• 73.5%
• 17.6%
• 99.8%

2. Please explain this value in one sentence.

3. Calculate the specificity. Write the formula and show your work.

Group of answer choices

• 97%
• 73.5%
• 17.6%
• 99.8%

4. Please explain this value in one sentence.

5. Based on your results, would you recommend that the CES-D should be used to identify and refer people with clinical depression?

Group of answer choices

• No. Although sensitivity is very high, specificity is not high enough and will result in too many people being referred for unnecessary diagnosis and treatment. Another instrument should be considered.
• Yes. Sensitivity is very high, and although specificity is not high enough, it is important to identify all the people who needs to be referred for diagnosis and treatment. This instrument is good.

6. Calculate the positive predictive value. Write the formula and show your work.

7. Please explain this value in one sentence.

8. Calculate the negative predictive value. Write the formula and show your work.

9. Please explain this value in one sentence.