DrugEpi 3-6 Study Design Exercises Module 3 Introduction Content Area: Analytical Epidemiology...
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Transcript of DrugEpi 3-6 Study Design Exercises Module 3 Introduction Content Area: Analytical Epidemiology...
DrugEpi 3-6 Study Design Exercises
Module 3 IntroductionContent Area: Analytical EpidemiologyEssential Question (Generic): Is there an association between the hypothesized cause and the disease?Essential Question (Drug Abuse Specific): Is there an association between the hypothesized cause and drug use?Enduring Epidemiological Understanding: Causal hypotheses can be tested by observing exposures and diseases of people as they go about their daily lives. Information from these observational studies can be used to make and compare rates and identify associations.
Synopsis
In Module 3, students explore how hypotheses are tested epidemiologically. Students begin to uncover and develop the following epidemiological concepts and skills: the meaning of the term “association;” the need for a control group; uses of the 2x2 table in calculating risks and relative risks; experimental study design; the importance of ethics in human research; observational study designs used in epidemiology; and the strengths and limitations of each design.
Lesson 3-1: Associations and the 2x2 TableLesson 3-2: Experimental Study - Buprenorphine ExampleLesson 3-3: An Actual Randomized Controlled TrialLesson 3-4: Observational Studies of Natural Experiments - Sensation-Seeking ExampleLesson 3-5: Fundamentals of Study DesignLesson 3-6: Study Design Exercises
DrugEpi 3-6 Study Design Exercises
Module 3 - Analytical Epidemiology
Lesson 3-6 Study Design Exercises
Content
• Reinforcement of study design concepts with an exercise to identify “What is My Design?”
• An Epi Team challenge that pulls together the study design elements, called “Connections between Designs, Flow Diagrams, and 2x2 Tables”
• Reinforcement of relative strengths and limitations of each study design with a key exercise that examines “Which Design is Best?”
Big Ideas
• The flow diagrams show how each study design is carried out in time
• Each study design can be expressed in a 2x2 table format that connects to the depiction in the flow diagram
• Each study design has strengths, limitations, and trade-offs. Usually, the studies with greater scientific rigor also have higher costs and time to completion. Choice of study designs depends on several circumstances.
This project is supported by a Science Education Drug Abuse Partnership Award, Grant Number 1R24DA016357-01, from the National Institute on Drug Abuse,
National Institutes of Health.
DrugEpi 3-6 Study Design Exercises
1. How is this disease distributed?
Health-related conditions and behaviors are not distributed uniformly in a population. They have unique distributions that can be described by how they are distributed in terms of person, place, and time.
2. What hypotheses might explain the distribution of disease?
Clues for formulating hypotheses can be found by observing the way a health-related condition or behavior is distributed in a population.
3. Is there an association between the hypothesized cause and the disease?
Causal hypotheses can be tested by observing exposures and diseases of people as they go about their daily lives. Information from these observational studies can be used to make and compare rates and identify associations.
4. Is the association causal? Causation is only one explanation for an association between an exposure and a disease. Because observational studies are complicated by factors not controlled by the observer, other explanations also must be considered.
5. What should be done when preventable causes of disease are found?
Policy decisions are based on more than the scientific evidence. Because of competing values - social, economic, ethical, environmental, cultural, and political factors may also be considered.
Essential Questions Enduring Understandings
Where are we?
DrugEpi 3-6 Study Design Exercises
Controlled Trial
Cohort Study
Case-Control
Cross-Sectional
Observational
Experimental
Review
DrugEpi 3-6 Study Design Exercises
Controlled Trial
Cohort Study
Case-Control Study
Cross-Sectional Study
Healthy PeopleHealthy People
E
Random Assignment
E
DZ
DZ
DZ
DZ
Healthy PeopleHealthy People
E
E
DZ
DZ
DZ
DZ
DZ
DZ
E
E
E
E
E
E
DZ
DZ
Review - Flow diagrams of the Four Study Designs
DrugEpi 3-6 Study Design Exercises
Controlled Trial
Healthy People
-
Healthy People
E
Random Assignment
E
DZ
DZ
DZ
DZ
Cohort Study
Healthy People
-
Healthy People
E
E
DZ
DZ
DZ
DZ
Cross-Sectional Study
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E
E
DZ
DZ
EPI Team Challenge: What’s My Design?
Case-Control Study
-
DZ
DZ
E
E
E
E
DrugEpi 3-6 Study Design Exercises
DZ DZ
E
E
d
b
ca
Flow Diagram 2x2 Table
&
“fit”
Healthy People
-
Healthy People
E
E
DZ
DZ
DZ
DZ
EPI Team Challenge: Connections Between Flow Diagrams and 2x2 Tables
DrugEpi 3-6 Study Design Exercises
Controlled Trial
Healthy People
-
Healthy People
E
Random Assignment
E
DZ
DZ
DZ
DZ
Cohort Study
Healthy People
-
Healthy People
E
E
DZ
DZ
DZ
DZ
Cross-Sectional Study
-
E
E
DZ
DZ
EPI Team Challenge: Which Design Is Best?
Case-Control Study
-
DZ
DZ
E
E
E
E
DrugEpi 3-6 Study Design Exercises
Time
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Healthy People
-
Healthy People
E
Random Assignment
E
DZ
DZ
DZ
DZ
Controlled Trial
Time
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Healthy People
-
Healthy People
E
E
DZ
DZ
DZ
DZ
Cohort Study
Time
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DZ
DZ
E
E
E
E
Case-Control Study
Time
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
-
E
E
DZ
Cross-Sectional Study
DZ
What’s My Design?
Controlled Trial
Cohort Study
Case-Control Study
Cross-Sectional Study
DrugEpi 3-6 Study Design Exercises
Epidemiologist is involved during the entire time from exposure to disease.
Assign treatment and control groups.
Follow through time and compare risk of disease in treatment group with risk of disease in control group.
Give exposure to treatment group, but not controls.
Practice Clue
Trial
What’s My Design?
DrugEpi 3-6 Study Design Exercises
Assign treatment and control groups.
Clue 1
Begin Epi Team Challenge
Trial
What’s My Design?
DrugEpi 3-6 Study Design Exercises
Observational
Study
Flow Diagram
DZ
-
DZ
E
E
E
E
Clue 2
Case-Control Study
What’s My Design?
DrugEpi 3-6 Study Design Exercises
Observational
Study
Flow Diagram
Clue 3
Cohort, Case-Control, and Cross-Sectional Studies
What’s My Design?
DrugEpi 3-6 Study Design Exercises
Observational
Study
Flow Diagram
E
E
-
DZ
DZClue 4
Cross Sectional Study
What’s My Design?
DrugEpi 3-6 Study Design Exercises
Follow through time and compare risk of disease in exposed group with risk of disease in the unexposed group.
Clue 5
Trial and Cohort Study
What’s My Design?
DrugEpi 3-6 Study Design Exercises
Healthy People
Flow Diagram
-
Healthy People
E
E
Random Assignment
Non-Observational
Study
Clue 6
Trial
What’s My Design?
DrugEpi 3-6 Study Design Exercises
Select a group of people with disease and a similar group of people without disease.
Clue 7
Case-Control Study
What’s My Design?
DrugEpi 3-6 Study Design Exercises
E
E
DZ
DZ
DZ
DZ
Flow Diagram
Observational
Study
DZ
-
Cohort Study
What’s My Design?
Clue 8
DrugEpi 3-6 Study Design Exercises
Epidemiologist is involved during the entire time from exposure to disease.
Clue 9
Trial and Cohort Study
What’s My Design?
DrugEpi 3-6 Study Design Exercises
What’s My Design?
Follow through time and compare risk of disease in treatment group with risk of disease in control group.
Give exposure to treatment group, but not controls.
Trial
Clue 10
DrugEpi 3-6 Study Design Exercises
Select a study sample.
What’s My Design?
Trial, Cohort Study, Case-Control Study, and Cross-
Sectional Study
Clue 11
DrugEpi 3-6 Study Design Exercises
Epidemiologist gathers data only at that one point in time.
What’s My Design?
Cross-Sectional Study
Clue 12
DrugEpi 3-6 Study Design Exercises
Flow Diagram
-
DZ
DZ
What’s My Design?
Case-Control Study
Clue 13
DrugEpi 3-6 Study Design Exercises
DZ
DZ
DZ
DZ
Flow Diagram
Cohort Study and Trial
What’s My Design?
Clue 14
DrugEpi 3-6 Study Design Exercises
Case-Control Study
Epidemiologist is involved after disease has occurred and relies on subjects’ memories to gather information about exposure.
Select a group of people with disease and a similar group of people without the disease.
Compare percent of exposed people in the two groups.
Ask both groups about their exposures in the past.
What’s My Design?
Clue 15
DrugEpi 3-6 Study Design Exercises
Cohort Study
Epidemiologist is involved during the entire time from exposure to disease.
Select a healthy study sample.
Follow through time and compare risk of disease in exposed group to risk of disease in unexposed group.
Observe who has and has not been exposed.
Clue 16
What’s My Design?
DrugEpi 3-6 Study Design Exercises
Cross-Sectional Study
Ask each person about both exposure and disease at that point in time.
Epidemiologist gathers data only at that one point in time.
Disease risk in exposed group is compared to disease risk in unexposed group.
Select a study sample.
Clue 17
What’s My Design?
DrugEpi 3-6 Study Design Exercises
DZ DZ
E
E
d
b
ca
Flow Diagram 2x2 Table
&
“fit”
Healthy People
-
Healthy People
E
E
DZ
DZ
DZ
DZ
EPI Team Challenge: Designs, Flow Diagrams, and 2x2 Tables
DrugEpi 3-6 Study Design Exercises
DZ DZ
E
Ea
2x2 Table
Where do these people “fit” in the 2x2 table?
Flow Diagram
Controlled Trial
Healthy PeopleHealthy People
E
E
DZ
DZ
DZ
DZ
Random Assignment
DrugEpi 3-6 Study Design Exercises
DZ DZ
E
Eb
Flow Diagram 2x2 Table
Healthy PeopleHealthy People
E
E
DZ
DZ
DZ
DZ
Random Assignment
Where do these people “fit” in the 2x2 table?
Controlled Trial
DrugEpi 3-6 Study Design Exercises
DZ DZ
E
E
c
Flow Diagram 2x2 TableFlow Diagram
Healthy PeopleHealthy People
E
E
DZ
DZ
DZ
DZ
Random Assignment
Where do these people “fit” in the 2x2 table?
Controlled Trial
DrugEpi 3-6 Study Design Exercises
DZ DZ
E
E
d
2x2 TableFlow Diagram
Healthy PeopleHealthy People
E
E
DZ
DZ
DZ
DZ
Random Assignment
Where do these people “fit” in the 2x2 table?
Controlled Trial
DrugEpi 3-6 Study Design Exercises
DZ DZ
E
E
c
Flow Diagram 2x2 Table
Where are these people in the flow diagram?
Cohort Study
Healthy PeopleHealthy People
E
E
DZ
DZ
DZ
DZ
DrugEpi 3-6 Study Design Exercises
DZ DZ
E
Ea
2x2 Table
Where are these people in the flow diagram?
Flow Diagram
Cohort Study
Healthy People
E
E
DZ
DZ
DZ
DZ
Healthy People
DrugEpi 3-6 Study Design Exercises
DZ DZ
E
E
d
Flow Diagram 2x2 Table
Where are these people in the flow diagram?
Cohort Study
Healthy People
E
E
DZ
DZ
DZ
DZ
Healthy People
DrugEpi 3-6 Study Design Exercises
DZ DZ
E
Eb
Flow Diagram 2x2 Table
Where are these people in the flow diagram?
Cohort Study
Healthy People
E
E
DZ
DZ
DZ
DZ
Healthy People
DrugEpi 3-6 Study Design Exercises
DZ DZ
E
Ea
Where do these
people go in the
2x2 table?
2x2 Table Flow Diagram
Case-Control Study
DZ
DZ
E
E
E
E
DrugEpi 3-6 Study Design Exercises
DZ DZ
E
E
c
Where do these
people go in the
2x2 table?
Flow Diagram2x2 Table
Case-Control Study
DZ
DZ
E
E
E
E
DrugEpi 3-6 Study Design Exercises
Flow Diagram
DZ DZ
E
E b
2x2 Table
Where do these
people go in the
2x2 table?
Case-Control Study
DZ
DZ
E
E
E
E
DrugEpi 3-6 Study Design Exercises
Flow Diagram
DZ DZ
E
E
d
2x2 Table
Where do these
people go in the
2x2 table?
Case-Control Study
DZ
DZ
E
E
E
E
DrugEpi 3-6 Study Design Exercises
DZ DZ
E
E aFlow Diagram
2x2 Table
Where do these
people go in the
2x2 table?
Cross-Sectional Study
E
E
DZ
DZ
DrugEpi 3-6 Study Design Exercises
DZ DZ
E
E
c
Flow Diagram
2x2 Table
Where do these
people go in the
2x2 table?
Cross-Sectional Study
E
E
DZ
DZ
DrugEpi 3-6 Study Design Exercises
DZ DZ
E
E
d
Flow Diagram
2x2 Table
Where do these
people go in the
2x2 table?
Cross-Sectional Study
E
E
DZ
DZ
DrugEpi 3-6 Study Design Exercises
DZ DZ
E
Eb
Flow Diagram
2x2 Table
Where do these
people go in the
2x2 table?
Cross-Sectional Study
E
E
DZ
DZ
DrugEpi 3-6 Study Design Exercises
Controlled Trial
Healthy People
-
Healthy People
E
Random Assignment
E
DZ
DZ
DZ
DZ
Cohort Study
Healthy People
-
Healthy People
E
E
DZ
DZ
DZ
DZ
Cross-Sectional Study
-
E
E
DZ
DZ
EPI Team Challenge: Which Design Is Best?
Case-Control Study
-
DZ
DZ
E
E
E
E
DrugEpi 3-6 Study Design Exercises
Cross-Sectional Study
Case-Control Study
Cohort Study
Trial
Main WeaknessesMain StrengthsStudy Designs
1 5
62
3 7
84
Epi Team ChallengeWhich Design is Best?
DrugEpi 3-6 Study Design Exercises
Cross-Sectional Study
Case-Control Study
Cohort Study
Trial
Main WeaknessesMain StrengthsStudy Designs
1 5
62
3 7
84
Cross-Sectional
CohortCase-
Control Controlled
Trial
Epi Team ChallengeWhich Design is Best?
DrugEpi 3-6 Study Design Exercises
Cross-Sectional Study
Case-Control Study
Cohort Study
Trial
Main WeaknessesMain StrengthsStudy Designs
1 5
62
3 7
84
Fastest
Which study design is the fastest?
Which Design is Best?
DrugEpi 3-6 Study Design Exercises
Cross-Sectional Study
Case-Control Study
Cohort Study
Trial
Main WeaknessesMain StrengthsStudy Designs
1 5
62
3 7
84
Fastest
Time Consuming
Time Consuming
Which study designs are the most time consuming?
Which Design is Best?
DrugEpi 3-6 Study Design Exercises
Cross-Sectional Study
Case-Control Study
Cohort Study
Trial
Main WeaknessesMain StrengthsStudy Designs
1 5
62
3 7
84
Fastest
Time Consuming
Most Scientifically Sound
Which study design is the most scientifically sound?
Time Consuming
Which Design is Best?
DrugEpi 3-6 Study Design Exercises
Cross-Sectional Study
Case-Control Study
Cohort Study
Trial
Main WeaknessesMain StrengthsStudy Designs
1 5
62
3 7
84
Fastest
Time Consuming
Most Scientifically Sound
Can Study Rare Diseases
Which study design is best for studying rare diseases?
Time Consuming
Which Design is Best?
DrugEpi 3-6 Study Design Exercises
Cross-Sectional Study
Case-Control Study
Cohort Study
Trial
Main WeaknessesMain StrengthsStudy Designs
1 5
62
3 7
84
Fastest
Time Consuming
Most Scientifically Sound
Possible Time-Order Confusion
Possible Time-Order Confusion
Can Study Rare Diseases
Which study designs do not identify the time order of exposure and disease?
Time Consuming
Which Design is Best?
DrugEpi 3-6 Study Design Exercises
Cross-Sectional Study
Case-Control Study
Cohort Study
Trial
Main WeaknessesMain StrengthsStudy Designs
1 5
62
3 7
84
Fastest
Time Consuming
Most Scientifically Sound
Best Measure of Exposure
Can Study Rare Diseases
Least Expensive
Relatively Less Expensive and Relatively Fast
Possible Error in Recalling Exposures
Most Accurate Observational Study
Which Design Is Best?
Time Consuming
Unethical for Harmful exposuresMost Expensive
Most Expensive
Possible Time-Order Confusion
Possible Time-Order Confusion
Least Confidence in Findings
Good Measure of Exposure
It depends ….
Which Design is Best?
DrugEpi 3-6 Study Design Exercises
It depends . . .
regulations
time urgency
how much is known about the association
money
whether the exposure is believed to be beneficial
. . . on the situation regarding
DrugEpi 3-6 Study Design Exercises
4 Study Designs
2nd
3rd
4thWeaker
Stronger1st
Randomized Trial
Cohort Study
Case-Control Study
Cross-Sectional Study
Which Design Is Best?
DrugEpi 3-6 Study Design Exercises
4 Study Designs
2nd
3rd
Longest
Time
Shortest
Time
1st
Cross-Sectional Study
Case-Control Study
Cohort Study
Trial
Which Design Is Best?
3rd
DrugEpi 3-6 Study Design Exercises
4 Study Designs
2nd
3rd
4th
Most
Expensive
Least
Expensive
1st Cohort Study
Case-Control Study
Cross-Sectional Study
Cross-Sectional Study
Case-Control Study
Cohort Study
Trial
Which Design Is Best?
DrugEpi 3-6 Study Design Exercises
4 Study Designs
2nd
3rd
4th
Least
Accurate
Most
Accurate
1st Cohort Study
Case-Control Study
Cross-Sectional Study
Trial
Cohort Study
Case-Control Study
Cross-Sectional Study
Which Design Is Best?
DrugEpi 3-6 Study Design Exercises
4 Study Designs
2nd
3rd
4th
Least
Sound
Most
Sound
1st
Trial
Cohort Study
Case-Control Study
Cross-Sectional Study
Which Design Is Best?
DrugEpi 3-6 Study Design Exercises
CDC
Does this all make sense
to you?
There are four basic study designs for testing hypotheses.
Each design has a different plan for assessing exposure and disease.
The plan for each design can be understood by: 1) thinking of a train ride from exposure to disease, and 2) constructing a flow diagram.
Whatever the study design, the assessment of exposure and disease “fits” into a 2x2 table so that a sample’s exposure and disease can be classified, risks calculated, risks compared, and inferences made.
Review - Making Sense
DrugEpi 3-6 Study Design Exercises
Big Ideas in this Lesson (3-6)
Big Ideas
The flow diagrams show how each study design is carried out in time
Each study design can be expressed in a 2x2 table format that connects to the depiction in the flow diagram
Each study design has strengths, limitations, and trade-offs. Usually, the studies with greater scientific rigor also have higher costs and time to completion. Choice of study designs depends on several circumstances.
This project is supported by a Science Education Drug Abuse Partnership Award, Grant Number 1R24DA016357-01, from the National Institute on Drug Abuse,
National Institutes of Health.
Re-Cap
DrugEpi 3-6 Study Design Exercises
1. How is this disease distributed?
Health-related conditions and behaviors are not distributed uniformly in a population. They have unique distributions that can be described by how they are distributed in terms of person, place, and time.
2. What hypotheses might explain the distribution of disease?
Clues for formulating hypotheses can be found by observing the way a health-related condition or behavior is distributed in a population.
3. Is there an association between the hypothesized cause and the disease?
Causal hypotheses can be tested by observing exposures and diseases of people as they go about their daily lives. Information from these observational studies can be used to make and compare rates and identify associations.
4. Is the association causal?
Causation is only one explanation for an association between an exposure and a disease. Because observational studies are complicated by factors not controlled by the observer, other explanations also must be considered.
5. What should be done when preventable causes of disease are found?
Policy decisions are based on more than the scientific evidence. Because of competing values - social, economic, ethical, environmental, cultural, and political factors may also be considered.
Essential Questions Enduring Understandings
Next Lesson
DrugEpi 3-6 Study Design Exercises
What hypotheses might explain the distribution of disease?
Is there an association between the hypothesized cause and the disease?
Causal hypotheses can be tested by observing exposures and diseases of people as they go about their daily lives. Information from these observational studies can be used to make and compare rates and identify associations.
Is the association causal? Causation is only one explanation for finding an association between an exposure and a disease. Because observational studies are flawed, other explanations must also be considered.
What should be done when preventable causes of disease are found?
Individual and societal health-related decisions are based on more than scientific evidence. Because of competing values, social, economic, and political factors must also be considered.
Did the disease prevention strategy work?
The effectiveness of a strategy can be evaluated by making and comparing rates of disease in populations of people who were and were not exposed to the strategy. Costs, trade-offs and alternative strategies must also be considered.
5.
6.
2.
3.
4.
Clues for formulating hypotheses can be found by observing the way a health-related condition or behavior is distributed in a population.
Next LessonEssential Questions Enduring Understandings
How is this disease distributed?
1. Health-related conditions and behaviors are not distributed uniformly in a population. They have unique distributions that can be described by how they are distributed in terms of person, place, and time.