Epi 2 Flashcards
Outbreak or population level investigation
- establish problem
- determine key questions
- define cases and noncases
- record all events
5.collect data on epidemiologic factors - look for patterns and assoications between risk factor and disease
- form and test hypotheses about disease control
- plan and implement control methods
change in
awareness
record keeping
observation
population composition
magnitude of effect
how big is the difference between groups or individuals with and without a particular risk factor
significance of effect/p value
could the difference we found be just due to chance variation
precision or uncertainty in estimate
how certain are we of the size of the effect
ratio of incidence rates
risk ratio or relative risk=incidence with risk factor/incidence without risk factor
prevalence ratio
prevalence with risk factor/prevalence without risk factor
interpretation of ratio
1-incidence/prevalence are the same in both group
>1-incidence/prevalence is higher for those with the risk factor
<1 incidence/prevalence is lower for those with the risk factor (protective)
difference between incidence rates
attributable risk=incidence with risk factor-incidence without risk factor
attributable fraction (exp)
attributable risk/incidence in high risk group
attributable prevalence
prevalence with risk factor-prevalence without risk factor
attributable fraction of prevalence (exp)
attributable prevalence/prevalence in high risk group
P value
probability that a difference of this size or larger would be observed if there really was no difference between the groups
P value range
P=.20 a 1 out of 5 chance
P=.05 a 1 out of 20 chance
P=.01 a 1 out of 100 chance
confidence interval
potential range around the calculated effect size in which the real difference should be based on sample size and alpha
