Measures of Risk and Association

Question 1

single blind RCT

Answer 1

researchers do not tell participants if being given treatment or control

Question 2

double blind RCT

Answer 2

neither pt’s or researchers know who is getting placebo or treatment

-prevent bias due to demand characteristics or placebo effect

Question 3

open labeled clinical trials

Answer 3

both reasearchers and pt’s know which treatment is admin
-still randomized
-uncontrolled (all pt’s get same treatment)

Question 4

crossover study

Answer 4

half pt’s get treatment I for a period then get placebo (treatment II)

other half gets placebo first then treatment

so pt serves as their own control (w/i subject)

Question 5

crossover pros/cons

Answer 5

order effect
carryover effect (side effects of a drug)

good for improvement of chronic illness

Question 6

absolute risk reduction

Answer 6

simple/direct measure of treatment impact
-dep on background baseline risk bc van vary based on population but clinically more interpretable

null value = 0

Question 7

number needed to treat

NNT

Answer 7

number of pts needed to be treated by intervention to prevent an adverse event
-dep on efficacy of intervention and baseline risk

= 1/ARR

Question 8

relative risk

RR

Answer 8

risk of even in the treatment group vs standard of care/control

null value = 1.0 so if
RR< 1.0 = dec risk and beneficial treat
RR>1.0= inc risk and harmful treat

Question 9

relative risk reduction

Answer 9

proportion of baseline risk that is removed by new therapy = 1-RR

indicated magnitude of risk dec of the adverses event

Question 10

number needed to harm

Answer 10

how many subjects need to be exposed to risk fact for one extra person to experience adverse event

1/risk difference