Reminders

Question 1

Necessary cause

Answer 1

the cause must be present for the outcome to happen

however, the cause can be present without the outcome happening

Question 2

Sufficient cause

Answer 2

if the cause if present, the outcome must occur

however, the outcome can occur without the cause being present

Question 3

Types of selection bias

Answer 3

volunteer
non-response
exclusion
healthy worker

Question 4

Types of information bias

Answer 4

differential/nondifferential
recall
interviewer
loss to follow up
reporting (social desirability, wish)
misclassification

Question 5

Types of observational studies

Answer 5

case report
case series
case-control = always retrospective, based on disease
cohort = based on exposure, prospective or retrospective
cross sectional = exposure and disease at the same time (no RR)
nested case-control
case-cohort
N-of-1
case-crossover