Functions & Formulae

Each applied formula has its own function page, with a signature, implementations, and tests.

Absolute risk estimation function

r(E,N) = R

Maps the number of people who have a new event during a stated period, and the number at risk at the start of that period, to the probability of the event over the period. The result is a risk, tied to the length of the period, not a rate per unit of time. Moving a risk to a different period, such as a model cycle, goes through a rate and is covered on the Transition Probability page.

  • Absolute risk as an incidence proportion

    R = E / N

    Divides the number of new events during the period by the number of people at risk at its start. In epidemiology the same quantity is called the incidence proportion, attack rate or cumulative incidence. It gives the comparator-arm baseline risk that a decision model applies relative treatment effects to.