Quantifying risk

Question 1

What calculate to Quantify risk case control

Answer 1

Odds ratio

Question 2

What calculate to quantify risk of cohort study

Answer 2

Relative risk

Question 3

Odds ratio

Answer 3

Vertical: OR= ad/bc

Question 4

Relative risk

Answer 4

Horizontal: RR= a/(a+b)/ c/(c+d)
Or
Incidence of exposed/ incidence of unexposed

Question 5

Attributable risk

Answer 5

AR= Exposed risk - unexposed risk

Question 6

If prevalence is low, then …

Answer 6

OR = RR

Question 7

Absolute risk reduction

Answer 7

Difference in risk with intervention compared to control

ARR= Cumulative incidence placebo - cumulative incidence treatment

Question 8

Numbers needed to treat

Answer 8

1/ ARR

Question 9

Numbers needed to harm

Answer 9

1/AR

Question 10

Cohort study

Answer 10

Start with exposure look for diff outcome

Question 11

Case control study

Answer 11

Start with outcome and look at diff exposure

Question 12

Case control bias

Answer 12

Recall bias

Question 13

Cross sectional study

Answer 13

Assess exposures and outcome same time

Question 14

Cross sectional study measures

Answer 14

Disease prevalence
Show risk factor association with disease
Does NOT establish causality

Question 15

Phase 1

Answer 15

Is safe?

Question 16

Phase 2

Answer 16

Does it work?

Treatment efficacy, optimal dosing, and adverse effects

Question 17

Phase 3

Answer 17

Is it good or better?

Compare treatment to current standard of care

Question 18

Phase 4

Answer 18

Detect rare or long term adverse effects

Question 19

Sensitivity

Answer 19

TP/(TP+FN) or 1-false negative rate
SN-N-OUT= When Negative rule OUT disease
True positive rate
Probability when test positive, disease is present

Question 20

When use high sensitivity test and what mean?

Answer 20

Screening disease with low prevalence, high sensitivity indicate low false negative rate

Question 21

Specificity

Answer 21

TN/ (TN+FP) or 1-false positive rate
SP-P-IN = when Positive rule IN disease
True negative rate
Probability when test negative , disease is absent

Question 22

When use high specificity test and what highly specific test mean?

Answer 22

Confirmation after positive screening test

Highly specific indicate low false positive rate

Question 23

If increase sensitivity, then what happen to negative predictive value

Answer 23

Increase

Question 24

Decrease specificity does what to positive predictive value?

Answer 24

Decrease

Question 25

Raising cutoff point does what?

Answer 25

Increase specificity and PPV

Decrease sensitivity and NPV

Question 26

Decreasing cutoff point does what?

Answer 26

Increase sensitivity and NPV

Decrease specificity and PPV

Question 27

Incidence rate eqn

Answer 27

new cases/ # ppl at risk

Question 28

Prevalence eqn

Answer 28

existing cases/ total # ppl in pop

Question 29

Precision

Answer 29

consistency and reproducibility (reliability)

Question 30

Increased precision does what?

Answer 30

Decrease st dev

Increase statistical power

Question 31

Random error does what?

Answer 31

Decrease precision

Question 32

Accuracy

Answer 32

Validity of measure

Question 33

Systematic error does what?

Answer 33

Decrease accuracy