RESS Flashcards
What is the scientific method?
Observation Propose or modify hypothesis Test hypothesis Reject hypothesis and modify it OR not reject hypothesis and re-test
Is there truth in science?
No
What are the 3 requirements of a health outcome?
Validity, reliability, responsiveness
What is validity?
Whether it accurately measures what it purports to measure
What is reliability?
Same result if retest?
What is responsiveness?
Does it detect changes when they occur?
Definition of a fact?
Confirmed to such a degree that disagreement would be perverse
Definition of a hypothesis?
A testable statement that describes an observation
How do you verify a hypothesis?
Not falsifying it
4 things a hypothesis must be?
Plausible
Testable
Have direction
Precise
Economics is about limited ______ and unlimited_____?
Resources
‘Wants’
What is opportunity cost?
Choosing A over B means giving up B
What is technical efficiency?
What is the best way to deliver a programme?
What is allocative efficiency?
Producing something that matches demand
Resources being allocated between activities in such a way as to maximise benefit is called?
Economic efficiency
What is the ‘margin’ in economics?
The next step
What are the marginal benefits and costs?
The benefits and costs of taking the next step
Does efficiency consider WHO benefits?
No
What is equity?
Fairness or justice of the distributions
What is the cost and what is the outcome for cost benefit?
Both are monetary value
What is the cost and what is the outcome for cost effectiveness
Cost: monetary value
Outcome: Natural units e.g. life years saved
What is the cost and what is the outcome for cost utility?
Cost: monetary value
Outcome: utility values e.g. QALYs
What type of cost analysis do NICE use?
Cost utility analysis
What is EQ-5D?
Way of finding out QALYs, a survey that uses country specific data for its algorithm
What perspectives might be considered in determining cost perspective?
Societal (absence from work etc)
Health care system
Cost effectiveness ratio =?
Cost/QALYs
What is the incremental cost effectiveness ratio?
Change in cost/ change in effectiveness
What does a cost-effectiveness acceptability curve show?
The probability that the intervention is cost effective compared with the alternative.
Cost effectiveness threshold aka willingness to pay
against
probability
In normal distribution which average is used?
Mean and SD
In skewed distribution which average is used?
Median and IQR
What graph do you use to find the distribution of a continuous variable?
Histogram
Mortality=?
Number dying from the disease/number dying in the period
Case fatality=?
Number dying from the disease/number with the disease (in the period)
A risk ratio of 1 would indicate what?
The exposure has no impact
A risk ratio of more than 1 =?
Exposure is harmful
What is the P value?
Probability that the results were due to the hypothesis (rather than chance)
Effect size
A quantitative measure of the strength of a phenomenon
What is a confidence interval
X% (normally 95%) certain that the true population mean falls within a specified range e.g. +-0.05
Correlation should not be used in which 5 cases?
- There is a non-linear relationship between variables
- There are outliers
- There are distinct sub-groups, for example, if we mix two samples together such as healthy controls and disease cases
- One or both of the variables is not normally distributed. 5. One or both of the variables is non-numeric.
Calculation of a risk ratio requires? And so what sort of study can this be used in?
Incidence
Cohort
Risk ratio is a measure of
Relative risk
Odds are
number of times the event occurs divided by the number of times it does not occur.
Risk/probability is?
Number of outcomes / total number of possible outcomes
What is the odds ratio for?
Represents the relative risk for a case-control study (when there is no incidence.)
Linear regression allows us to?
Make predictions
What is the null hypothesis of the chi-squared test
That there is no relationship between the variables
When can chi-squared not be used?
Small sample size- it is too likely to reject the null hypothesis in this case (but a correction can be used)
If P is more than what value can you not reject the null hypothesis in a chi-squared test?
0.05
What is a ‘failure’ in a study?
Someone leaving/dying etc.
Leaving the study before the event occurs, or entering the study after the start of the study, is known as ?
Censoring
Right censored data occurs when….?
the people in the study did not reach a failure before the end of the study.
Left censoring is when….?
We are not certain what happened to people before the time at which they entered the study.
A common example is when people already have the disease of interest when the study starts.
The survival function is defined as….?
the chance of survival until a certain time
The hazard function is defined as….?
the chance of instantaneous failure at any one time
What is an odds ratio?
the ratio of the odds of having a disease to the odds of not having a disease.
