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Flashcards in Critical appraisal Deck (22)
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1

Confounder

variable associated with both exposure and outcome

2

Best type of study design to minimize effects of confounders

RCT

3

Cons of doing RCT

Expensive, time consuming, difficult for rare events

4

how to calculate relative risk

incidence of intervention / incidence of control

5

Relative risk reduction

ARR = (risk in intervention - risk in control)
divided by
risk in control group
(or 1-RR)

6

case control studies

identify groups based on a specific OUTCOME, see if they have certain exposures

7

cohort studies

follow subjects with a specific EXPOSURE and evaluate outcomes, exposure not under investigator's control

8

best method to study rare diseases

case control (go back and look at their history)

9

sensitivity

given that the disease is present, the probability that the test is positive

10

specificity

given that the disease is absent, the probability that the test is negative

11

sensitivity (equation)

TP/(TP+FN)

12

specificity (equation)

TN/(TN+FP)

13

positive predictive value

given that the test is positive, the probability that the disease is present

14

negative predictive value

given that the test is negative, the probability that the disease is absent

15

PPV and NPV vary with...

disease prevalence

16

PPV (equation)

TP/(TP+FP)

17

NPV (equation)

TN/(TN+FN)

18

Power of a study (equation)

1 - Type II error (the chance that the p value will not be statistically significant despite a true difference between the two groups)

19

Type 1 error

the probability that the difference observed is due to chance

20

p-value (definition)

the probability that the difference observed in the study is simply due to chance (type 1 error)

21

LR for a positive test

sensitivity/(1-specificity)

22

LR for a negative test

(1-sensitivity)/specificity