PUBH 401 Final Exam Questions And All
Correct Answers.
Ecologic Fallacy - Answer - observations made at the group level may not represent the
exposure-disease relationship at the individual level
- incorrectly ascribing group characteristics to individual members of a group
Confounder - Answer
How do you design a randomized trial/ experiment? - Answer 1. Begin with a defined
population.
2. Randomly assign people to new treatment or current treatment.
3. Follow the subjects in each group through time.
4. At the end of the study compare how many improved with new treatment to how many
improved with current treatment.
5. Can also compare a treatment group to a group with no treatment.
What are the three randomized trial phases required by the FDA? - Answer - Phase I
- Phase II
- Phase III
Phase I - Answer - first test of the new drug (on human)
- use small groups of 20 to 80 people
- goal is to look at toxicity levels and pharmacologic effects:
~determine a safe dosage range
~ identify side effects
Phase II - Answer - after drug passes Phase I
- Larger trials with 100 to 200 patients
- goal is to test efficacy and relative safety of the drug
Phase III - Answer - after drug passes Phase II
, Phase IV - Answer - post-marketing study
- goal is delineate additional information including the drug's risks, benefits, and optimal use as
the drug comes into general use by the public
- used to avoid lawsuits
What are the ethical issues regarding randomized trials? - Answer - Randomization is only
ethical when we do not know whether drug A is better than drug B.
- Researchers may have some indication that one drug is better than another, but they do not
know for certain.
- The same is true for using a placebo. Researchers do not know for certain that the
treatment/drug under study is better than a placebo.
When can you stop a trial early? - Answer - Harmful effects - WHI (Women's Health Initiative)
and cancer, heart disease
- Beneficial effects - PHS (Physician's Health Study) and aspirin
- An external data monitoring board makes that decision.
Look at data gathered thus far and decide if there is adequate evidence to support a harm or
benefit.
What is a cohort study? - Answer Collect exposure information then follow people to see who
gets the disease.
How do you design a cohort study? - Answer 1. Start with group of people by either:
A)Selecting people based on exposure status
Example: The World Trade Center Health study
B)Creating a defined population first and then assessing exposure status
Example: The Multiethnic Cohort study of cancer
2. Record information on exposure status. Gather other relevant information.
3. Follow the group over a defined time period.
4. Assess disease status.
5. Perform data analysis and calculate appropriate measures of risk.
Correct Answers.
Ecologic Fallacy - Answer - observations made at the group level may not represent the
exposure-disease relationship at the individual level
- incorrectly ascribing group characteristics to individual members of a group
Confounder - Answer
How do you design a randomized trial/ experiment? - Answer 1. Begin with a defined
population.
2. Randomly assign people to new treatment or current treatment.
3. Follow the subjects in each group through time.
4. At the end of the study compare how many improved with new treatment to how many
improved with current treatment.
5. Can also compare a treatment group to a group with no treatment.
What are the three randomized trial phases required by the FDA? - Answer - Phase I
- Phase II
- Phase III
Phase I - Answer - first test of the new drug (on human)
- use small groups of 20 to 80 people
- goal is to look at toxicity levels and pharmacologic effects:
~determine a safe dosage range
~ identify side effects
Phase II - Answer - after drug passes Phase I
- Larger trials with 100 to 200 patients
- goal is to test efficacy and relative safety of the drug
Phase III - Answer - after drug passes Phase II
, Phase IV - Answer - post-marketing study
- goal is delineate additional information including the drug's risks, benefits, and optimal use as
the drug comes into general use by the public
- used to avoid lawsuits
What are the ethical issues regarding randomized trials? - Answer - Randomization is only
ethical when we do not know whether drug A is better than drug B.
- Researchers may have some indication that one drug is better than another, but they do not
know for certain.
- The same is true for using a placebo. Researchers do not know for certain that the
treatment/drug under study is better than a placebo.
When can you stop a trial early? - Answer - Harmful effects - WHI (Women's Health Initiative)
and cancer, heart disease
- Beneficial effects - PHS (Physician's Health Study) and aspirin
- An external data monitoring board makes that decision.
Look at data gathered thus far and decide if there is adequate evidence to support a harm or
benefit.
What is a cohort study? - Answer Collect exposure information then follow people to see who
gets the disease.
How do you design a cohort study? - Answer 1. Start with group of people by either:
A)Selecting people based on exposure status
Example: The World Trade Center Health study
B)Creating a defined population first and then assessing exposure status
Example: The Multiethnic Cohort study of cancer
2. Record information on exposure status. Gather other relevant information.
3. Follow the group over a defined time period.
4. Assess disease status.
5. Perform data analysis and calculate appropriate measures of risk.
