Question 1

Which of the following is a technique to reduce information bias?

Accepted Answer

A)  Use memory aids and validate exposures. 
B)  Provide standardized training sessions and protocols. 
C)  Use standardized collection forms. 
D)  Try to ensure that questions are clearly understood. 
E)  All are correct. 
A)  Use memory aids and validate exposures. 
B)  Provide standardized training sessions and protocols. 
C)  Use standardized collection forms. 
D)  Try to ensure that questions are clearly understood. 
E)  All are correct. E

Question 2

A double-blind study of a vaccine is one in which:

Accepted Answer

A)  the study group receives the vaccine and the control group receives a placebo. 
B)  neither observers nor subjects know the nature of the placebo. 
C)  neither observers nor subjects know which subject receives the vaccine and which receives a placebo. 
D)  neither the study group nor the control group knows the identity of the observers. 
E)  the control group does not know the identity of the study group. 
A)  the study group receives the vaccine and the control group receives a placebo. 
B)  neither observers nor subjects know the nature of the placebo. 
C)  neither observers nor subjects know which subject receives the vaccine and which receives a placebo. 
D)  neither the study group nor the control group knows the identity of the observers. 
E)  the control group does not know the identity of the study group. C

Question 3

In a study to determine the incidence of a chronic disease, 150 people were examined at the end of a three-year period. Twelve cases were found, giving a cumulative risk of 8%. Fifty other members of the initial cohort could not be examined; 20 of these 50 could not be examined because they died. Which source of bias may have affected the study?

Accepted Answer

A)  Information bias: interviewer/abstractor bias 
B)  Hawthorne effect 
C)  Selection bias: survival bias 
D)  Information bias: recall bias 
A)  Information bias: interviewer/abstractor bias 
B)  Hawthorne effect 
C)  Selection bias: survival bias 
D)  Information bias: recall bias C

Question 4

Which of the following is not a method for controlling the effects of confounding in epidemiologic studies?

Accepted Answer

A)  Randomization 
B)  Stratification 
C)  Matching 
D)  Blinding 
E)  Restriction 
A)  Randomization 
B)  Stratification 
C)  Matching 
D)  Blinding 
E)  Restriction

Question 5

An epidemiologic experiment is performed in which one group is exposed to a suspected factor and the other is not. All individuals with an odd hospital admission number are assigned to the second group. The main purpose of this procedure is to:

Accepted Answer

A)  ensure a double-blind study. 
B)  prevent observer bias with respect to the factor. 
C)  prevent observer bias with respect to the outcome. 
D)  improve the likelihood that the two groups will be comparable with regard to known and unknown confounding factors. 
E)  guarantee comparability of the two groups with regard to other relevant factors. 
A)  ensure a double-blind study. 
B)  prevent observer bias with respect to the factor. 
C)  prevent observer bias with respect to the outcome. 
D)  improve the likelihood that the two groups will be comparable with regard to known and unknown confounding factors. 
E)  guarantee comparability of the two groups with regard to other relevant factors.

Question 6

Surgeons at Hospital A report that the mortality rate at the end of a one-year follow-up after a new coronary bypass procedure is 15%. At Hospital B, the surgeons report a one-year mortality rate of 8% for the same procedure. Before concluding that the surgeons at Hospital B have vastly superior skill, which of the following possible confounders would you examine?

Accepted Answer

A)  The severity (stage) of disease of the patients at the two hospitals at baseline 
B)  The starting point of the one-year follow-up at both hospitals (after operation versus after discharge) 
C)  Difference in the postoperative care at the two hospitals 
D)  Equally thorough follow-up for mortality 
E)  All are correct. 
A)  The severity (stage) of disease of the patients at the two hospitals at baseline 
B)  The starting point of the one-year follow-up at both hospitals (after operation versus after discharge) 
C)  Difference in the postoperative care at the two hospitals 
D)  Equally thorough follow-up for mortality 
E)  All are correct.

Question 7

The purpose of matching in a case-control study is to select the controls in such a way that the control group has the same distribution as the cases with respect to certain confounding variables.

Accepted Answer

A) True 
 B)False

Question 8

You are investigating the role of physical activity in heart disease and suggest that physical activity protects against having a heart attack. While presenting these data to your colleagues, someone asks if you have thought about confounders such as factor X. This factor X could have confounded your interpretation of the data if it:

Accepted Answer

A)  is a factor for some other disease, but not heart disease. 
B)  is a factor associated with physical activity and heart disease. 
C)  is a part of the pathway by which physical activity affects heart disease. 
D)  has caused a lack of follow-up of test subjects. 
A)  is a factor for some other disease, but not heart disease. 
B)  is a factor associated with physical activity and heart disease. 
C)  is a part of the pathway by which physical activity affects heart disease. 
D)  has caused a lack of follow-up of test subjects.

Question 9

The purpose of a double-blind study is to:

Accepted Answer

A)  achieve comparability of cases and controls. 
B)  reduce the effects of sampling variation. 
C)  avoid observer and interviewee bias. 
D)  avoid observer bias and sampling variation. 
E)  avoid interviewee bias and sampling variation. 
A)  achieve comparability of cases and controls. 
B)  reduce the effects of sampling variation. 
C)  avoid observer and interviewee bias. 
D)  avoid observer bias and sampling variation. 
E)  avoid interviewee bias and sampling variation.

Which of the following is a technique to reduce information bias?

A double-blind study of a vaccine is one in which:

Which of the following is not a method for controlling the effects of confounding in epidemiologic studies?

An epidemiologic experiment is performed in which one group is exposed to a suspected factor and the other is not. All individuals with an odd hospital admission number are assigned to the second group. The main purpose of this procedure is to:

The purpose of matching in a case-control study is to select the controls in such a way that the control group has the same distribution as the cases with respect to certain confounding variables.

The purpose of a double-blind study is to:

History and Scope of Epidemiology

Practical Applications of Epidemiology

Measures of Morbidity and Mortality Used in Epidemiology

Descriptive Epidemiology: Person, Place, Time

Sources of Data for Use in Epidemiology

Study Designs: Ecologic, Cross-Sectional, Case-Control

Study Designs: Cohort Studies

Experimental Study Designs

Measures of Effect

Screening for Disease in the Community

Epidemiology of Infectious Diseases

Epidemiologic Aspects of Work and the Environment

Molecular and Genetic Epidemiology

Social, Behavioral, and Psychosocial Epidemiology

Epidemiology As a Profession

Epidemiology and Health Policy

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Exam 10: Data Interpretation Issues

Which of the following is a technique to reduce information bias?

A double-blind study of a vaccine is one in which:

Which of the following is not a method for controlling the effects of confounding in epidemiologic studies?

An epidemiologic experiment is performed in which one group is exposed to a suspected factor and the other is not. All individuals with an odd hospital admission number are assigned to the second group. The main purpose of this procedure is to:

The purpose of matching in a case-control study is to select the controls in such a way that the control group has the same distribution as the cases with respect to certain confounding variables.

The purpose of a double-blind study is to:

History and Scope of Epidemiology

Practical Applications of Epidemiology

Measures of Morbidity and Mortality Used in Epidemiology

Descriptive Epidemiology: Person, Place, Time

Sources of Data for Use in Epidemiology

Study Designs: Ecologic, Cross-Sectional, Case-Control

Study Designs: Cohort Studies

Experimental Study Designs

Measures of Effect

Screening for Disease in the Community

Epidemiology of Infectious Diseases

Epidemiologic Aspects of Work and the Environment

Molecular and Genetic Epidemiology

Social, Behavioral, and Psychosocial Epidemiology

Epidemiology As a Profession

Epidemiology and Health Policy

Filters