Measures of impact Flashcards
what is use of population impact measurements
The most important use of measures of population impact is for the planning of public health
interventions, to predict the impact of removing, or changing, the distribution of the risk factor
on the frequency of disease in the population. This can also be interpreted as the fraction of all
cases in the population that is caused by the risk factor; and also as the probability that any case
in the population was caused by the risk factor (and has been used as such in court cases).
what is population impact
they estimate how much of the disease in the population is caused by the suspected risk factor.
what determines the generalisability of population impact?
Measures of population impact are specific to the population studied, and can only be generalised to populations with exactly the same distribution of risk factors. Risk factors that
are strongly associated but which are rare, like being exposed to an X-ray in pregnancy and
leukaemia in childhood, may have a large measure of effect but small measure of impact.
What is the population attributable risk (PAR)
is the absolute difference between the risk (or rate) in the whole population and the risk (or rate) in the unexposed group.
what is the difference between measures of impact and measures of effect
Measures of effect compare exposed and unexposed; and measures of impact compare
population and unexposed.
What are the assumptions in measures population impact
1) calculation assumes all associations between risk factors and our one is causal
2) removal if risk factor removes risk i.e. those previously exposed are now unexposed once removed risk factor
3) risk factor is removable and measured correctly
