Statistical Checklists & Applicability

Question 1

Define an aetiological study

Answer 1

Compare the risk of developing an outcome in one or more groups exposed to one or more risk factors e.g case control, cohort

Question 2

Define a diagnostic study

Answer 2

Compares a new test for diagnosing a condition with gold standard method

Question 3

Define sensitivity

Answer 3

Proportion of subjects with the disorder who have a positive result

Question 4

Define specificity

Answer 4

Proportion of subjects without the disorder who have a negative result

Question 5

Define positive predictive value

Answer 5

Proportion of subjects who have a positive result and have the disorder

Question 6

Define negative predictive value

Answer 6

Proportion of subjects who have a negative result and do not have the disorder

Question 7

Define pre test probability

Answer 7

The probability a subject will have the disorder

- also known as prevalence

Question 8

Define pre test odds

Answer 8

The odds a subject will have the disorder

Question 9

Define post test odds

Answer 9

The odds a subject who scores positive on the test actually has the disorder

Question 10

Define post test probability

Answer 10

The probability a subject who scores positive on the test actually has the disorder

Question 11

Sensitivity & specificity are effected by prevalence of a disorder. True/False

Answer 11

False - PPV & NPV are
PPV will decrease
NPV will increase
Therefore likelihood ratios can be more useful

Question 12

Serial testing increases specificity. True/False

Answer 12

True

Question 13

Parallel testing increases sensitivity. True/False

Answer 13

True

Question 14

Define a treatment study

Answer 14

Compare the effects of a new intervention with those of another intervention

Question 15

Define survival analysis

Answer 15

Studies the time between entry into a study and subsequent occurrence of an event

Question 16

Define median survival time

Answer 16

Time from the start of the study that coincides with a 50% probability of survival

Question 17

Define Kaplan-Meier survival analysis

Answer 17

Reviews event rates over the study period rather than just a specific time point
- Used to determine survival probabilities & proportions of individuals surviving

Question 18

Give an example of an input cost

Answer 18

Direct medical costs
Indirect non-medical costs
Indirect costs
Intangible costs

Question 19

Give an example of an output benefit

Answer 19

Associated economic effects
Natural units e.g survival
Utility units e.g QoL

Question 20

Define a cost of illness study

Answer 20

Measures all the costs associated with a particular condition
- Not a true economic analysis

Question 21

Define cost minimisation analysis

Answer 21

Interventions are being compared which produce the same beneficial outcome
- Aims to decide the least costly way of achieving the same outcome

Question 22

Define cost effectiveness analysis

Answer 22

Used when outcome is the same for alternative interventions but achieved by different mechanisms and to different degrees.
- Amount of improvement has to be factored into the analysis in addition to cost

Question 23

Define cost consequence analysis

Answer 23

Subtype of cost effectiveness analysis

Used when there is more than one outcome measure

Question 24

Define cost utility analysis

Answer 24

Used to make choices between interventions for different conditions in which the units of outcome differ

Question 25

What is the best known utility measure?

Answer 25

QALY

Question 26

Define cost benefit analysis

Answer 26

Compares the cost and benefits of different treatments for different patient groups by using a monetary value on the outcomes

• Result for each intervention is expressed as a ratio of economic benefits:costs
• Considers the opportunity cost rather than just direct cost (the loss of alternatives as one is chosen)

Question 27

What is a purposive sampling method?

Answer 27

Selection of subjects who have knowledge or experience of the area being investigated
- Commonly used

Question 28

What is a quota sampling method?

Answer 28

Subtype of purposive sampling, quotas are set of subjects with certain characteristics

Question 29

What is a convenience sampling method?

Answer 29

People selected based on ease/accessibility

Question 30

What is a snowball sampling method?

Answer 30

Researcher identifies subjects who are used to refer researchers on to other subjects in their social network

Question 31

Name a method of validating qualitative data

Answer 31

Member checks

Triangulation

Question 32

Name a method of minimising bias in qualitative data

Answer 32

Reflexivity

Bracketing