Research Study Designs

Question 1

What are the two study designs in medical research and the difference between the two?

Answer 1

1. Observational study designs (no intervention)

2. Experimental study designs (intervention)

Question 2

What are the five types of observational study designs?

Answer 2

1. Descriptive (also called “case-series”)
2. Case-control (also called”retrospective”)
3. Cross-sectional (also called “surveys” or “prevalence”)
4. Cohort (also called “prospective”)
5. Historical cohort

Question 3

What are the two goals of case-control (or retrospective) studies?

Answer 3

1. Causes and incidence of disease

2. Identification of risk factors

Question 4

What are three goals of cross-sectional (also called surveys or prevalence) studies?

Answer 4

1. Disease description
2. Diagnosis and staging
3. Disease processes, mechanisms

Question 5

What are three goals of cohort (also called prospective) studies?

Answer 5

1. Causes and incidence of disease
2. Natural history, prognosis
3. Identification of risk factors

Question 6

What are three types of experimental study designs (with controls)?

Answer 6

1. Parallel (also called concurrent) control trials
2. Sequential controls
3. External controls (including historical)

Question 7

What are two kinds of parallel (or concurrent) control studies?

Answer 7

1. Randomized

2. Not randomized

Question 8

What are two kinds of sequential control studies?

Answer 8

1. Self-controlled

2. Crossover

Question 9

What is the question that case-control studies aim to answer?

Answer 9

“What happened?”

Question 10

What is the direction of inquiry in relation to the direction of time for case-control studies?

Answer 10

Opposite the direction of time (i.e. looking backwards).

Question 11

What is the question that cross-sectional studies aim to answer?

Answer 11

“What is happening?”

Question 12

What is the direction of inquiry in relation to the direction of time for cross-sectional studies?

Answer 12

No direction of inquiry (i.e. looking at the present).

Question 13

What is the question that cohort studies (including retrospective/historical) aim to answer?

Answer 13

“What will happen?

Question 14

What is the direction of inquiry in relation to the direction of time for cohort (including retrospective/historical) studies?

Answer 14

In the same direction as time (i.e. looking into the future).

Question 15

What are three pro’s to randomized clinical trials?

Answer 15

1. Considered “Gold Standard”
2. Can conclude causality
3. Least amount of bias

Question 16

What are two con’s to randomized clinical trials?

Answer 16

1. Expensive

2. Long duration

Question 17

What are two pro’s to cohort studies?

Answer 17

1. Provides possible causes and effects

2. Biases can be controlled

Question 18

What is one con of cohort studies?

Answer 18

1. Loss of follow-up

Question 19

What are three pro’s of case control studies?

Answer 19

1. Less expensive
2. For rare diseases and events
3. For chronic diseases it’s good as a preliminary study

Question 20

What are three con’s of case control studies?

Answer 20

1. Prone to bias
2. Control group hard to find
3. Data might be incomplete

Question 21

What are two pro’s of cross-sectional studies?

Answer 21

1. Quick

2. Less expensive

Question 22

What are two con’s of cross-sectional studies?

Answer 22

1. Can be misleading

2. Low response rate (surveys)

Question 23

What are four important things to do when designing a study?

Answer 23

1. State a hypothesis, or at least some well-focused research questions.
2. Carefully define your study population.
3. Select an appropriate research design.
4. Ensure the objectivity, precision, and reliability of your measures.