Epidemiology Flashcards
Prevalence
=(all cases present at time point)/(total # of unit at that time)
Cumulative Incidence
=(# events during period of time)/(pop w/o dz at begin of time)
Attact rate
=(# of cases)/(total # of subject exposure)
Relative risk
cohort studies =(A/A+B)/(C/C+D) neg assoc <1 1 = no associ pos assoc > 1
Odds Ratio
Case-control studies =(AD)/(BC) neg assoc <1 1 = no associ pos assoc > 1
Risk difference
=Risk exp - risk unexp
Attributable risk %
=(RR-1)/RR
Population attributable risk %
=(Risk overall - Risk unexp)/Risk Overall
Prevented fraction
=1-RR
PPV
=TP/(TP+FP)
NPV
=TN/(TN+FN)
Sensitivity
=A/(A+C)
Specificity
=D/(B+D)
Mortality Rate
=(total # deaths from all causes in 1 year)/(pop at mid year)
Case-fatality rate
=(# deaths after dz onset or dx)/(#ind with the dz)
Incidence rate
=(#new events)/(total person-time at risk in pop)
proportionate mortality
=(# death from sp dz in time period)/(total # death in tat time period)
Type I error
False positive, alpha
Type II error
False negatvie, beta
Power
=1-beta
Outbreak Steps
- Prep for fieldwork
- Estimate the existence of outbreak
- Verify Dx
- Define and identify cases
- Describe and orient the data in terms of time, place, and subject
- Develop hypotheses
- Evaluate Hypotheses
- Refine hypothesis and carry out studies
- Implement control and prevention measures
- Communicate findings
