Behavioural and Biostats Flashcards
Collects data from a group of people to assess frequency of disease and related risk factors at a particular point in time
cross sectional study
compares a group of people with disease to a group without disease to look for prior exposures or risk factors
case control
compares a group with a given exposure or risk factor to a group without such exposure to see if exposure increased likelihood of disease
cohort
case control study calculates what
OR
cohort study calculates what
RR
cross sectional study calculates what
prevalence (NOT incidence)
clinical trial phase: is it safe?
phase 1, small number of healthy volunteers
clinical trial phase: does it work?
phase 2: small number of patients with disease of interest
clinical trial phase: is it as good or better?
phase 3: large number of patients randomly assigned to either treatment or placebo/best treatment available
clinical trial phase: can it stay?
phase 4: postmarketing surveillance of patients after treatment is approved
how does prevalence affect PPV and NPV?
increasing prevalence increases PPV and decreases NPV
odds ratios are used in what kind of studies
case control
relative risk is used in what studies
cohort studies
OR formula
how many people with disease had exposure
A/C / B/D
RR formula
how many people with exposure got disease
a/(a+b) / c/(c+d)
