Clinical trials

Question 1

Experimental study

Answer 1

One or more factors altered and effects examined

Question 2

Observational studies

Answer 2

Observations made without any interventions
- Cohort (follow over time)
- Case-control (retrospective)
- Cross-sectional (point in time)

Question 3

Controlled trials

Answer 3

Non-randomised or randomised (best)

Question 4

RR

Answer 4

Risk ratio, one population vs another
Used in binary outcomes

Question 5

OR

Answer 5

Probability of event occurring
Odds = probability of an event occurring / probability of an event not occurring (like a ratio)

Question 6

Type 1 error (alpha)

Answer 6

False positive

Question 7

Type 2 error (beta)

Answer 7

False negative

Question 8

Types of bias

Answer 8

Experimental - analysis, selection, measurements
Subject - placebo effect
Attrition - drop out

Question 9

Good control group

Answer 9

best practice/placebo, historical data, blinding, similar groups, inclusion/exclusion criteria

Question 10

Kaplan-Meier curve

Answer 10

Measure progression over time (survival, progression-free, disease-free)
Time since recruitment, censors subjects