Study Designs Recap

Question 1

What is temporal association?

Answer 1

Causation

Question 2

What types of study is temporal associated assumed?

Answer 2

• RCT
• case control
• prospective + retrospective cohort
  NOT cross sectional

Question 3

Advantages + disadvantages of randomised control trials

Answer 3

advantages
- Can state causation
- Can compare to current treatment standards
- Removes selection bias
.
disadvantages
- time consuming
- prevent generalisation
- more expensive

Question 4

What is a confounding factor?

Answer 4

A factor that has influenced the results of the study without being accounted for

Question 5

How is a cohort study conduced?

Answer 5

Select a cohort then observe exposure + event
- exposed vs unexposed
- disease present or absent in both groups
- compare results

Question 6

What are the types of cohort study?

Answer 6

• prospective: a cohort of participants is recruited + then followed up for some time going forward present time
• retrospective: a cohort of participants is recruited from the past + data is collected from records past time

Question 7

Advantages and disadvantages of cohort studies

Answer 7

advantages
- good for studying range of outcomes
- can establish exposure preceded outcome
- good for rare exposures

disadvantages
- time consuming
- expensive
- not good for rare outcomes

Question 8

How is a randomised control trial conducted?

Answer 8

Participants randomly assigned to exposure then event observed + results compared
e.g new drug vs current drug/placebo

Question 9

How is a case control study conduced?

Answer 9

• Select cases then controls are matched
• data is collected retrospectively > looks back at exposed + unexposed

Question 10

Differentiate between retrospective cohort study + case control

Answer 10

• retrospective cohort: exposure > outcome
• case control: exposure < outcome

Question 11

Advantages + disadvantages of case control study

Answer 11

advantages:
- can investigate multiple exposures for a single outcome
- good for rare disease
- no loss to follow up

disadvantages:
- not good for rare exposure
- can only study one outcome
- potential for reverse causality

Question 12

Define bias

Answer 12

Any trend or deviation from the truth in data collection, analysis, interpretation + publications which cause false conclusions