Flashcards in Behavioural and Biostats Deck (20):

1

## Collects data from a group of people to assess frequency of disease and related risk factors at a particular point in time

### cross sectional study

2

## compares a group of people with disease to a group without disease to look for prior exposures or risk factors

### case control

3

## compares a group with a given exposure or risk factor to a group without such exposure to see if exposure increased likelihood of disease

### cohort

4

## case control study calculates what

### OR

5

## cohort study calculates what

### RR

6

## cross sectional study calculates what

### prevalence (NOT incidence)

7

## clinical trial phase: is it safe?

### phase 1, small number of healthy volunteers

8

## clinical trial phase: does it work?

### phase 2: small number of patients with disease of interest

9

## clinical trial phase: is it as good or better?

### phase 3: large number of patients randomly assigned to either treatment or placebo/best treatment available

10

## clinical trial phase: can it stay?

### phase 4: postmarketing surveillance of patients after treatment is approved

11

## how does prevalence affect PPV and NPV?

### increasing prevalence increases PPV and decreases NPV

12

## odds ratios are used in what kind of studies

### case control

13

## relative risk is used in what studies

### cohort studies

14

## OR formula

###
how many people with disease had exposure

A/C / B/D

15

## RR formula

###
how many people with exposure got disease

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

16

## Attributable risk formula

###
proportion of disease attributable to the exposure

a/a+b - c/c+d

17

## relative risk reduction formula

###
proportion of risk reduction attributable to intervention

1-RR

18

## absolute risk reduction forumula

###
difference in risk attributable to intervention vs. control

c/c+d - a/a+b

19

## number needed to treat formula

###
number of patients who need to be treated for1 1 person to benefit

1/ARR

20