Topic 20: association vs causation

Question 1

Describe causation

Answer 1

• Valid association = not automatic causation
• Association ≠ causation
• Causal = exposure directly causes outcome
• Criteria need to be met

Question 2

Give the Bradford Hill criteria for causality

Answer 2

1) Temporality
2) Strength
3) Biological gradient
4) Reversibility
5) Consistency
6) Plausibility

Question 3

Define temporality

Answer 3

• Exposure must precede outcome

Question 4

Define strength

Answer 4

• Stronger the association = more likely causal

Question 5

Define biological gradient

Answer 5

• Dose response association between exposure + outcome

Question 6

Define reversibility

Answer 6

• Removing exposure reduces incidence of outcome

Question 7

Define consistency

Answer 7

• Association observed in multiple occasions = replication of results

Question 8

Define plausability

Answer 8

• Theoretically sound explaination for observed association = biologically plausible

Question 9

Define analogy

Answer 9

• Other analogous observed findings in literature

Question 10

Define coherence

Answer 10

• Association fits with known facts from in vitro experiments

Question 11

Define specificity

Answer 11

• Exposure associated only with outcom of interest = no other outcome

Question 12

Describe the necessary cause

Answer 12

• If A is a necessary cause of outcome = presence of outcome implies presence of A
• Presence of A alone = doesn’t imply outcome will occur

Question 13

Describe sufficient cause

Answer 13

• If A is sufficient cause of outcome = presence alone can cause outcome
• But B may also cause outcome = presence of outcome doens’t imply presence of A