RESS lectures term 3 Flashcards
what are the 4 key economic concepts used in Health Economics?
- opportunity costs
- economic efficiency
- marginal analysis
- equity
what are the three main types of Economic Evaluation?
what’s the difference between them?
which is mainly used by NICE?
cost benefit analysis (CBA)
- everything is given a monetary value
cost effectiveness analysis (CEA)
- uses natural units (eg number of cases detected)
cost utility analysis (CUA)
- uses QALYs
- NICE mainly uses
main difference between these is how outcomes are measured
nb other less used ones are:
- cost-consequence analysis (CCA)
- cost-minimisation analysis (CMA)
what is the definition of opportunity cost?
the value of forgone benefit which could be obtained from a resource in its next best alternative use
(ie the loss of other alternatives when one alternative is chosen)
what are the two different types of efficiency?
what’s the difference?
technical efficiency:
- meeting a given objective at least cost possible/how best to deliver a programme (or achieve a given objective)
- eg shall surgery for tonsillectomy be provided by way of day surgery or inpatient surgery?
allocative efficiency:
- whether to allocate resources to a programme or whether to allocate more or less resources to it
- eg shall surgery for tonsillectomy be provided or an outpatient clinic for asthma?
what is does marginal analysis involve?
comparing the benefit from the ‘next step’ (marginal benefit) with the cost of taking the next step (marginal cost)
nb not interested in average benefit or cost, looking at incremental changes and where to draw the line until we are not prepared to accept the size of the marginal benefit for said high marginal cost
what is the difference between equity and efficiency?
efficiency looks at the total benefit without considering who actually benefits
equity is another criterion for allocating resources based on what benefits matter most to society
- concerned with the fairness or justice of the distribution of costs and benefits
for something to be considered to be a FULL economic evaluation what two criteria must it fulfill?
- both costs and consequences are considered
- must be comnparison of two or more alternatives (even if other one is ‘do nothing’)
what does dominance mean (in health economics)?
the intervention costs less and is, at least, as effective as the comparator
basically it’s cheaper and probably better so is a no-brainer in terms of funding
cost effectiveness analysis (CEA)
- how does it measure outcomes?
- pros?
- cons?
measures outcomes using ‘natural units’
- eg lives saved, symptom free days etc
pros:
- clear/easily understandable by lay person
- common/popular
cons:
- many healthcare programmes have multiple objectives, hard to compare: no clear idea of the relative importance between them
- secondary outcomes are not included, eg side effects/unintended consequences etc
cost benefit analysis (CBA):
- what outcome does it measure?
- pros?
- cons?
outcomes measured in monetary terms, everything converted to having a monetary value
pros:
- can make comparrisons outside of health, eg with education
cons:
- difficulty with valuation of health outcomes in monetary terms, so many variables, stuff is more valuable to some people than others etc
cost utility analysis (CUA):
- how are outcomes measured?
- pros?
- cons?
outcomes measured in Quality Adjusted Life Years (QALYs) gained
- combines life years and quality of those years (mortality + morbidity)
pros:
- measures quality + quantity of life gained
- easily comparable across treatment areas
- measure includes effects of side effects/inintended secondary outcomes
cons:
- calculating QALYs is time-consuming + costly
- dependent on method/scale used (different questionnaires may give different outcomes)
- equity issues, more QALYs to gain, may favour well over sick, genders, social class etc
QALYs:
- definition of one QALY?
- QALY when dead?
one QALY = one year of life lived in ‘perfect’ health
0 = dead
- nb can get negative values with questionnaire (ie suffering is worse than being dead)
give an example of a questionaire used to calculate quality of life, and thus QALYs?
EQ-5D
what is HES?
what’s it used for?
hospital episode statistics
- statistics collected by all hospitals in the NHS about out-patients/in-patients/maternity/A+E
- nb doesn’t include stats from primary or social care
health economics use this data, collected by the NHS, for economic evaluation
what is the ICER (incremental cost-effectiveness ratio?
how is it calculated?
ICER = difference in costs / difference in consequences
calculates the cost per extra unit of benefit
threshold for cost-effectiveness:
- aka?
- what is it?
- what is NICE’s?
willingness-to-pay threshold
basically adopt an initiative if ICER < threshold
NICE threshold is £20,000 - £30,000 per QALY
what is a health related state?
another way of saying outcome
(ie as opposed to an exposure)
eg death is a health related state (but smoking and age are more likely to be exposures)
describe the process of the scientific method?
1) observations
2) propose/modify hypothesis
3) test hypothesis
4) reject or not reject hypothesis
if reject: go back to stage 2
if not reject: retest the hypothesis
name and explain 3 different types of valid keyword search techniques
truncation
- represents multiple characters
- eg anorexi* = anorexia, anorexic
adjacency searching
- use ‘adj’ to find words near each other in an articles record
- eg eating adj disorder = eating related disorder, eating and drinking disorder
wild cards
- use the ? or # to search for different spellings
- eg behavio?ral = behavioural, behavioral (one charcter, or none)
- eg wom#n = women, woman (one character)
what measure of the average and what measure of spread would you use in:
- normally distributed data?
- non-normally/skewed data?
normally distributed:
- mean
- standard deviation
non-normally distributed
- median
- IQR
describe what a positively skewed data set looks like
and negatively skewed
positively skewed:
- there is a long TAIL going off to the RIGHT
- the majority of the data is towards the left
negatively skewed:
- there is a long TAIL going off to the LEFT
- the majority of the data is towards the right
what charts would you use for plotting:
- one continuous variable?
- two continuous variables plotted against each other?
one continuous variable
- histogram (or maybe box plot, but not great)
two continuous variable against each other
- scatter plot
what is point prevalence?
the same thing as prevalence
just slightly different term
what is the definition of case fatality rate?
number dying in period / number with the disease (in period)(prevalence)
how would you interpret a relative risk (risk ratio) of 1? the exposure:
- is protective?
- has no impact?
- is harmful?
explain this
has no impact
We are comparing 2 groups – exposed and unexposed.
Relative risk is a ratio, so a value of 1 means a ratio of 1:1 which means that the risk for the exposed is the same as the unexposed and therefore the exposure has no more (or less) impact than the control
Relative risk (risk ratio) – or odds ratio (though calculated differently, same interpretation)
- 1 = has no impact (have same risk of disease whether exposed to exposure or not)
- <1 = exposure is protective
- > 1 = exposure is harmful
what is the formula for relative risk (or risk ratio or odds ratio)?
risk in exposed group / risk in unexposed group
what does the p-value measure?
the PROBABILITY of an event occuring if your null hypothesis is correct
so a small p value means that there is a very small chance of getting the results you got if there was no actual difference between the two groups
nb it doesn’t tell you how accurate your statistical test is
what is standard error a measure of?
precision
what are the three different types of health outcome?
- record-based
- biological/clinical
- clinician/patient reported
definitions of:
- validity?
- reliability?
- responsiveness?
validity
- measures accurately what it is meant to meaasure
- eg using BMI rather than weight as a measure of obesity
reliability
- if you do the test again, you get the same result
responsiveness
- can detect real changes when they occur
- eg a continuous QoL scale is more responsive than a categorical measure
give definitions on these types of data:
- continuous?
- discrete?
- ordinal?
- nominal?
continuous:
- numerical value, no limitations on value
- eg weight (even if recorded in whole units)
discrete:
- numerical value, limits on values
- eg no. of hospital appointments
ordinal:
- ordered categories
- eg stage of disease, grades for exams
nominal:
- non-ordered categories
- eg sex, blood group
what is the likert scale?
what sort of data does it produce?
1 = definitely disagree 2 = partly disagree 3 = neutral 4 = partly agree 5 = definitely agree
ordinal data
what do QALYs measure?
length AND quality of life
how do you measure BMI? incl units
weight (in kg) / height (in metres) squared
