UPSC-CMS 2018 - Community Medicine PYQs Practice Questions

Q: The yield of a screening test CAN NOT be increased by which of the following?

Including entire population. ***Including entire population*** - Including the entire population, especially if it contains many individuals at **low risk** for the disease, would lead to a larger number of tests performed with a comparatively lower number of positive results, thus **decreasing the yield**. - **Screening yield** refers to the proportion of positive test results in the screened population or the number of new cases identified, and including a large low-risk group dilutes this proportion. *Including high risk population* - Targeting a **high-risk population** increases the **prevalence** of the disease within the screened group, leading to more true positives and a higher yield. - This strategy ensures that screening resources are focused on those most likely to benefit from early detection. *Improved sensitivity* - A screening test with **improved sensitivity** is better at identifying individuals who truly have the disease, leading to fewer **false negatives**. - By increasing the detection rate of actual cases, higher sensitivity directly contributes to a **greater screening yield** by detecting more true positive cases. *Improved specificity* - A screening test with **improved specificity** is better at correctly identifying individuals who do not have the disease, leading to fewer **false positives**. - However, improved specificity **does not increase the number of true cases detected**—it only reduces false positives, thus improving the **positive predictive value (PPV)** but not necessarily the screening yield itself. - While it makes positive results more reliable, it does not contribute to finding more actual disease cases in the population. [Practice more Community Medicine PYQs on OnCourse]

Question 1

What are the characteristics of ideal health indicators?

Accepted Answer

They should be valid, reliable, sensitive, specific, feasible and relevant

Answer

They should be mainly valid, reliable and relevant but need not be feasible

Answer

They should be mainly valid, reliable and sensitive but need not be specific

Answer

They should be mainly valid, reliable and feasible but need not be sensitive

Question 2

Which one of the following statements regarding predictive value of a positive test is true?

Accepted Answer

It tells the probability that a patient with positive test has the disease in question

Answer

It does not tell about diagnostic power of test

Answer

The more prevalent the disease, the less accurate the test is

Answer

It tells the probability that a patient with positive test does not have the disease in question

Question 3

The yield of a screening test CAN NOT be increased by which of the following?

Accepted Answer

Including entire population

Answer

Including high risk population

Answer

Improved sensitivity

Answer

Improved specificity

Question 4

Which one of the following statements regarding the growth chart is NOT true?

Accepted Answer

It is used as a tool for action against the Anganwadi worker

Answer

It is used as a tool for growth monitoring and diagnosis

Answer

It is used for planning and policy making

Answer

It is used as a tool for teaching and evaluation of effectiveness of programme

Question 5

A well of contaminated water resulted in an outbreak of diarrhoea in a community. Which type of epidemic will this exposure present with?
 1.Propagated epidemic 
 2.Common source - continuous exposure 
 3.Common source - point exposure

Accepted Answer

3 only

Answer

1, 2 and 3

Answer

2 only

Answer

1 and 2 only

Question 6

Which one of the following experiments/trials is a part of non-randomized trials?

Accepted Answer

Uncontrolled trial

Answer

Before and after comparison studies

Answer

Natural experiment

Answer

Risk factor trial

Question 7

What is the relative risk of developing tuberculosis among tobacco users as per the information given below?

Accepted Answer

2.67

Answer

3.90

Answer

0.48

Answer

1.33

Question 8

What is the attributable risk percent (etiologic fraction) of tobacco for developing tuberculosis as per the information given below? Tobacco users Tuberculosis Total Present Absent Yes 40 80 120 No 10 70 80 Total 50 150 200

Accepted Answer

62.5%

Answer

70.6%

Answer

50.5%

Answer

80.6%

Question 9

What is the sensitivity of EEG for detecting brain tumours as per the information given below?

Accepted Answer

90%

Answer

99.99%

Answer

0.07%

Answer

85%

Question 10

Asymptomatic carriers of pathogenic organisms are called:

Accepted Answer

Healthy carrier

Answer

Incubatory carriers

Answer

Pseudo carriers

Answer

Convalescent carriers

UPSC-CMS 2018 — Community Medicine