Measures of Association

Question 1

What is the Counterfactual Theory (Opposite)?

Answer 1

All else being equal, the outcome if the exposure didn’t occur

Question 2

What does the Counterfactual outcome assume?

Answer 2

Exchangability

Question 3

Exchangeability = Comparability with respect to…

Answer 3

…all other determinants of outcome

Question 4

What is an absolute difference?

Answer 4

Subtracting frequencies

Question 5

What is a relative difference?

Answer 5

Division (ratio) of frequencies

Question 6

Between absolute and relative differences, which will typically be smaller?

Answer 6

Absolute

Question 7

Define Risk

Answer 7

Probability of Outcome in an individual group

Question 8

What is Risk also known as?

Answer 8

Incidence Risk (IR)

Question 9

How do you calculate Probability of Outcome in the Exposed?

Answer 9

A / (A+B)

Question 10

How do you calculate Probability of Outcome in the Non-Exposed?

Answer 10

C / (C+D)

Question 11

What is Absolute Risk Reduction (ARR)?

Answer 11

Risk difference of the outcome attributable to exposure difference between groups

Question 12

What is ARR also known as?

Answer 12

Attributable Risk (AR)

Question 13

What is Relative Risk Reduction (RRR)?

Answer 13

Relative reduction in risk; (ARR / R unexposed)

Question 14

What is Number Needed to Treat (NNT)?

Answer 14

pts needed to be treated to receive the stated benefit/harm

Question 15

How do you calculate NNT?

Answer 15

(1 / ARR) in decimal format

Question 16

How do you calculate Risk Ratio (RR)?

Answer 16

(Risk of Outcome in Exposed / Risk of Outcome in Non-Exposed)

Question 17

What is RR also known as?

Answer 17

Relative Risk

Question 18

What three, possibly four, factors must be included when interpreting ratios?

Answer 18

1. Group comparison orientation
2. Direction of words
3. Magnitude
4. Adjustments, if any

Question 19

What is a Forest Plot?

Answer 19

Just describe it..

Question 20

Define Odds.

Answer 20

Frequency of an outcome occurring vs. not occurring

Question 21

How do you calculate OR in cases?

Answer 21

(A / C)

Question 22

How do you calculate OR in controls?

Answer 22

(B / D)

Question 23

What is another way to calculate OR?

Answer 23

[(A x D) / (B x C)]