positive likelihood ratio
sensitivity / (1 - specificity)
negative likelihood ratio
(1 - sensitivity) / specificity
odds ratio
(a/b) / (c/d)
relative risk
a/(a+b) / c/(c+d)
relative risk reduction
1 - RR
attributable risk
[a/(a+b)] - [c/(c+d)]
absolute risk reduction
c/(c+d) - a/(a+b)
number needed to treat
1/ARR
number needed to harm
1/AR
incidence
new cases / # people at risk
prevalence
existing cases / # total people in population
power
1 - beta