Biostats Flashcards
(18 cards)
Absolute risk reduction
event rate (control) - event rate (tx group)
relative risk reduction
absolute risk reduction / event rate (control group)
relative risk
event rate (tx group) / event rate (control group)
number needed to treat
1 / absolute risk reduction
attributable risk (risk difference)
incidence (exposed) - incidence (unexposed)
population attributable risk
incidence (total) - incidence (unexposed)
population attributable risk percent
(risk in population - risk in unexposed) / risk in population
number needed to treat
1 / attributable risk (risk difference)
attributable risk percent
attributable risk / incidence (exposed)
positive likelihood ratio
sensitivity / (1 - specificity)
negative likelihood ratio
(1 - sensitivity) / specificity
sensitivity
a / (a+c)
specificity
d / (d+b)
positive predictive value
a / (a+b)
negative predictive value
c / (c+d)
When are funnel plots used?
Funnel plots are commonly used in systemic reviews and search for publication bias
Selection bias definition
selection of subjects that are not representative of the study population
Referral bias definition
occurs when patients are sampled from specialized medical centers and therefore do not represent the general population
