Flashcards in biostats Deck (11):

1

## absolute risk reduction

### ARR = event rate in control group - event rate in tx group

2

## appropriate calculation for case-control study

### odds ratio

3

## appropriate calculation for cohort study

### relative risk

4

## odds ratio calculation

### ad/bc

5

## relative risk calculation

### a/(a+b)/ c/(c+d)

6

## attributable risk calculation

### a/(a+b) - c/(c+d)

7

## number needed to treat calculation

### 1/ARR

8

## number needed to harm calculation

### 1/AR

9

## confounding vs. effect modification

### when confounding is controlled for it usually reveals no significant difference between groups unlike effect modification (outcome modified by presence of another factor)

10

## Hawthorne effect

### study subjects change their behavior if they become aware that they are being studied

11