Flashcards in Lecture 3: Measures Of Association Deck (37)

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1

## Creating possible alternatives to events that already happened, for example someone got a disease instead of not having had it.

###
Counterfactual thinking/theory

Counter-to the-facts

2

## What assumption does counterfactual theory require?

### Assumption of exchangeability

3

## What is always in the columns of a 2x2 chart?

### Disease/Outcome

4

## Absolute differences is found by doing what with frequencies?

### Subtracting

5

## Relative differences is found by doing what with frequencies?

### Dividing

6

##
True or False:

Absolute differences are always larger than relative differences

###
False

Absolute is smaller

7

## Define ‘risk’

### The probability of an outcome in an individual group, exposed or not exposed

8

## Is risk considered a proportion or ratio?

###
Proportion

It is a simple percentage

9

## Absolute risk reduction formula

### Subtracting the absolute risk of those exposed - AR not exposed

10

## Relative risk reduction formula

###
ARR

——

Absolute Risk of the unexposed

11

## What does NNT stand for

### Number needed to treat

12

## What does NNH stand for?

### Number needed to harm

13

## Doe we want NNH or NNT to be smaller?

###
We want NNT to be small

We want NNH to be huge

14

## Give an example of NNT

###
It would take 8 patients on a drug for 1 person to get positive benefits

1 in 8 patients on this drug will get positive benefits

15

## How to calculate NNT/NNH?

###
1 divided by Absolute risk reduction

1

——

ARR

16

## how to calculate risk ratio?

### risk of outcome in exposed//////risk of outcome non-exposed=placebo

17

## The exposure or treatment group of interest, is always in the denominator when calculating risk ratio. T/F

###
false

always in numerator

18

## if risk ratio is >1

### the outcome is more likely to occur in the study than in the unexposed group

19

## if risk ratio is <1

### the outcome is less likely to occur in the study group than the unexposed group

20

## if risk ratio = 1

### outcomes are equally likely in both groups

21

## other names for risk ratio

###
odds ratio

hazard ratio

22

## interpret a RR = 1.53

### 53% more likely

23

## interpret a OR = 2.35

### outcome is 2.35 times more likely

24

## interpret a HR = 0.75

### outcome is 25% less likely to occur

25

## when interpreting a RR/OR/HR, there are 3 things you must include in your interpretation.....

###
1. groups you are comparing

2. direction of your results

3. magnitude

26

## visual representation of ratio data, horizontal plot allowing the comparison of multiple ratios and their differences from 1.0

### forest plot

27

## OR INTERPRETATION: association between baseline characteristics of firearm and pedestrian motor vehicle injury hospitalizations. Reference: white, Hispanic OR = 1.43

### hospitalization due to firearm injury or pedestrian motor vehicle injury, is 43% more likely to occur in Hispanic ethnicities than white.

28

## Odds is a ……?

###
ratio

29

## define 'odds'

###
frequency of an outcome occurring vs. not occurring

or

frequency of exposure vs. frequency of not being exposed

or

occurring/not occurring within one group

30