Statistical Checklists & Applicability Flashcards
Define an aetiological study
Compare the risk of developing an outcome in one or more groups exposed to one or more risk factors e.g case control, cohort
Define a diagnostic study
Compares a new test for diagnosing a condition with gold standard method
Define sensitivity
Proportion of subjects with the disorder who have a positive result
Define specificity
Proportion of subjects without the disorder who have a negative result
Define positive predictive value
Proportion of subjects who have a positive result and have the disorder
Define negative predictive value
Proportion of subjects who have a negative result and do not have the disorder
Define pre test probability
The probability a subject will have the disorder
- also known as prevalence
Define pre test odds
The odds a subject will have the disorder
Define post test odds
The odds a subject who scores positive on the test actually has the disorder
Define post test probability
The probability a subject who scores positive on the test actually has the disorder
Sensitivity & specificity are effected by prevalence of a disorder. True/False
False - PPV & NPV are
PPV will decrease
NPV will increase
Therefore likelihood ratios can be more useful
Serial testing increases specificity. True/False
True
Parallel testing increases sensitivity. True/False
True
Define a treatment study
Compare the effects of a new intervention with those of another intervention
Define survival analysis
Studies the time between entry into a study and subsequent occurrence of an event
Define median survival time
Time from the start of the study that coincides with a 50% probability of survival
Define Kaplan-Meier survival analysis
Reviews event rates over the study period rather than just a specific time point
- Used to determine survival probabilities & proportions of individuals surviving
Give an example of an input cost
Direct medical costs
Indirect non-medical costs
Indirect costs
Intangible costs
Give an example of an output benefit
Associated economic effects
Natural units e.g survival
Utility units e.g QoL
Define a cost of illness study
Measures all the costs associated with a particular condition
- Not a true economic analysis
Define cost minimisation analysis
Interventions are being compared which produce the same beneficial outcome
- Aims to decide the least costly way of achieving the same outcome
Define cost effectiveness analysis
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
Define cost consequence analysis
Subtype of cost effectiveness analysis
Used when there is more than one outcome measure
Define cost utility analysis
Used to make choices between interventions for different conditions in which the units of outcome differ
What is the best known utility measure?
QALY
Define cost benefit analysis
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)
What is a purposive sampling method?
Selection of subjects who have knowledge or experience of the area being investigated
- Commonly used
What is a quota sampling method?
Subtype of purposive sampling, quotas are set of subjects with certain characteristics
What is a convenience sampling method?
People selected based on ease/accessibility
What is a snowball sampling method?
Researcher identifies subjects who are used to refer researchers on to other subjects in their social network
Name a method of validating qualitative data
Member checks
Triangulation
Name a method of minimising bias in qualitative data
Reflexivity
Bracketing
