post_fr {freedom}

post_fr

Description

Calculate the posterior probability of freedom from the prior and the sensitivity of the system

Usage

post_fr(prior_fr, Se)

Arguments

prior_fr

The prior probability of freedom

Se

The sensitivity of the surveillance system

Details

The prior probability of freedom at the beginning of the surveillance initiative is a value that is based on some external evidence. Often 0.5 is used as a conservative estimate of the probability that the population is free from the disease. For subsequent time intervals in the surveillance system, the prior year's posterior probability of freedom is used (plus a risk of introduction) as the prior probability in this calculation.

Value

A vector

Examples

## Calculate the posterior probability of freedom after applying a
#sensitivity to a prior probability of freedom:
post_pf <- post_fr(0.5, 0.4)