Deck 8: Experimental Study Designs

Question 1

Clinical trials enroll individual subjects and enable randomization of subjects to receive or not receive the intervention.

Answer 1

True

Question 2

The Women's Health Initiative demonstrated that the benefits of hormone replacement therapy for cardiovascular disease had been overestimated.

Answer 2

True

Question 3

Intervention designs involve only controlled clinical trials.

Answer 3

False

Question 4

Randomized controlled trials at the community level are typically used in special situations where there is a simple intervention.

Question 5

A therapeutic trial involves the study of the effectiveness of a substance or program to prevent disease.

Question 6

Treatment crossover refers to any change of treatment for a patient in a clinical trial that involves a switch of study treatments.

Question 7

The purpose of the washout period is to control the carryover effect.

Question 8

An example of a famous heart disease program was the one conducted in North Carolina.

Question 9

In community intervention studies, it is important for the investigator to evaluate whether a program has achieved its intended results before assuming the benefits of the intervention.

Question 10

External validity is not connected with the selection of sample subjects.

Question 11

Controlled clinical trials enable researchers to:

A) test new drugs, new therapies, and new medical devices.
B) exercise control over who will receive an exposure.
C) identify definitive relationships between causes and effects.
D) All are correct.

Question 12

In contrast to observational studies, intervention studies are employed to:

A) generate knowledge about the etiology and natural history of disease.
B) formulate strategies for prevention.
C) test the efficacy of prevention measures.
D) All are correct.

Question 13

To assess clinical end points, investigators:

A) compare rates of disease.
B) compare rates of death.
C) compare rates of recovery.
D) All are correct.

Question 14

The Stanford Five-City Project, a major community trial designed to lower the risk of cardiovascular diseases, used two types of surveys to measure treatment-control differences across risk factors. What were they?

A) Both cross-sectional surveys of households and surveys of a cohort
B) Both community surveys and focus group surveys
C) Both surveys of clinical end points and surveys of outcomes
D) Both case-control groups and surveys of cohorts

Question 15

A prophylactic trial is designed to:

A) compare rates of disease, death, and recovery in a population.
B) measure how well drugs produce improvement in a patient's illness.
C) evaluate the effectiveness of a substance used to prevent disease.
D) estimate the impact of exposure on the incidence of disease.

Question 16

Surrogate endpoints for a clinical trial of a drug to control hypertension may include:

A) subclinical disease.
B) physical measures such as reduction in blood pressure.
C) occurrence of strokes and heart attacks.
D) subclinical disease and physical measures such as reduction in blood pressure.

Question 17

The purpose of a double-blind design in clinical trials is to reduce error that results from:

A) the way in which the outcome is assessed.
B) subjects' knowledge of their assignment to study conditions.
C) nonrandom assignment to study conditions.
D) the way in which the outcome is assessed and subjects' knowledge of their assignment to study conditions.
E) All are correct.

Question 18

Phase III clinical trials for a cancer drug involve:

A) initial testing in humans.
B) testing with different tumor types.
C) checking the new therapy against available therapies.
D) None of these is correct.

Question 19

The purpose of randomization is to reduce error that results from:

A) the way in which the outcome is assessed.
B) subjects' participation in the trial.
C) assignment to study conditions.
D) the way in which the outcome is assessed and assignment to study conditions.
E) All are correct.

Question 20

A major advantage of community trials is that they are able to:

A) control delivery of the intervention to many study units.
B) estimate directly the realistic impact of behavior change.
C) randomize subjects precisely to the study conditions.
D) All are correct.

Question 21

Which of the four stages of evaluation requires the collection of baseline information before the program starts?

A) Process evaluation
B) Impact evaluation
C) Outcome evaluation
D) None of these is correct.

Question 22

Which of the following types of health issues is likely to be addressed in community trials?

A) Smoking cessation
B) HIV/AIDS
C) Healthy eating
D) All are correct.

Question 23

To test the efficacy of a health education program in reducing the risk of foodborne and waterborne diseases, the residents of two Peruvian villages were given an intensive health education program. At the end of two years, the incidence rates of important waterborne and foodborne diseases in these villages were compared with those in two similar control villages without any education program. Which of the following study designs most appropriately characterizes this situation?

A) Cross-sectional study
B) Case-control study
C) Prospective cohort study
D) Historical prospective cohort study
E) Clinical trial
F) Community trial

Question 24

You would like to assess the effectiveness and efficiency of delivering health services through your clinic. After selecting a 10% sample of all patient visits during the past six months, you are able to characterize the patient population who used your clinic in terms of age, race, sex, method of referral, diagnostic category, therapy provided, method of payment, daily patient load, and clinic staff work schedules. Which of the following study designs most appropriately characterizes this situation?

A) Cross-sectional study
B) Case-control study
C) Prospective cohort study
D) Historical prospective cohort study
E) Clinical trial

Question 25

You are interested in finding out whether middle-aged men who have premature ventricular contractions (PVCs) are at greater risk of developing a myocardial infarction (heart attack) than men whose heartbeats are regular. Electrocardiogram (ECG) examinations are performed on all male office employees 35 years of age or older who work for oil companies in Houston. The ECG tracings are classified as irregular or regular. Five years later, myocardial infarction rates are compared between those with and those without baseline ECG irregularities. Which of the following study designs most appropriately characterizes this situation?

A) Cross-sectional study
B) Case-control study
C) Prospective cohort study
D) Historical prospective cohort study
E) Clinical trial

Question 26

To test the efficacy of vitamin C in preventing colds, army recruits are randomly assigned to one of two groups: one in which 500 mg of vitamin C is administered daily, and one in which 500 mg of a placebo is administered daily. Both groups are followed to determine the number and severity of subsequent colds. Which of the following study designs most appropriately characterizes this situation?

A) Cross-sectional study
B) Case-control study
C) Prospective cohort study
D) Historical prospective cohort study
E) Clinical trial

Question 27

The physical examination records of the incoming freshman class of 1935 at the University of Minnesota are examined in 1980 to see whether their recorded height and weight at the time of admission to the university are related to their chance of developing coronary heart disease by 1981. Which of the following study designs most appropriately characterizes this situation?

A) Cross-sectional study
B) Case-control study
C) Prospective cohort study
D) Historical prospective cohort study
E) Clinical trial

Question 28

The entire population of a given community is examined, and all who are judged to be free from bowel cancer are questioned extensively about their diets. These people then are followed for several years to see whether their eating habits will predict their risk of developing bowel cancer. Which of the following study designs most appropriately characterizes this situation?

A) Cross-sectional study
B) Case-control study
C) Prospective cohort study
D) Historical prospective cohort study
E) Clinical trial

Question 29

Match the following terms with their definitions.
Arm

A) A study plan on which all clinical trials are based
B) Any of the treatment groups in a randomized trial
C) The process of learning the key facts about a clinical trial before deciding whether or not to participate
D) A modification of the effect of the drug when administered with another drug
E) None of the above

Question 30

Match the following terms with their definitions.
Toxicity

A) A study plan on which all clinical trials are based
B) Any of the treatment groups in a randomized trial
C) The process of learning the key facts about a clinical trial before deciding whether or not to participate
D) A modification of the effect of the drug when administered with another drug
E) None of the above

Question 31

Match the following terms with their definitions.
Protocol

A) A study plan on which all clinical trials are based
B) Any of the treatment groups in a randomized trial
C) The process of learning the key facts about a clinical trial before deciding whether or not to participate
D) A modification of the effect of the drug when administered with another drug
E) None of the above

Question 32

Match the following terms with their definitions.
Informed consent

A) A study plan on which all clinical trials are based
B) Any of the treatment groups in a randomized trial
C) The process of learning the key facts about a clinical trial before deciding whether or not to participate
D) A modification of the effect of the drug when administered with another drug
E) None of the above

Question 33

Match the following terms with their definitions.
Efficacy

A) A study plan on which all clinical trials are based
B) Any of the treatment groups in a randomized trial
C) The process of learning the key facts about a clinical trial before deciding whether or not to participate
D) A modification of the effect of the drug when administered with another drug
E) None of the above