Evidence Based Medicine

Question 1

case control study

Answer 1

• retrospective
• 2 groups are: case (outcome present, e.g., COVID positive) and control (outcome absent, e.g., COVID negative)
• within each group, looking for whether exposure is present or absent (e.g., wearing a mask)
• odds ratio

Question 2

cohort study

Answer 2

• can be retrospective OR prospective
• 2 groups are: exposed cohort (exposed to risk factor) and unexposed cohort (not exposed to risk factor)
• within each group, looking for presence or absence of disease
• relative risk (risk ratio)

Question 3

confidence interval

Answer 3

CI = the percentage of all possible samples that can be expected to include the true population parameter

A 95% confidence level implies that 95% of the confidence intervals would include the true population parameter.

larger sample size = narrower width