Gamma prior for a hazard rate

Creates a Gamma prior distribution for the hazard rate \(\lambda\) of one group in an analysis of a time-to-event endpoint with exponential event times. The milestone survival probability at time \(t_0\) is \(S(t_0) = \exp(-\lambda t_0)\).

Usage

prior_gamma(shape, rate)

Arguments

shape, rate

Positive shape and rate parameters (the prior mean of the hazard is shape / rate).

Value

An object of class c("qdm_prior_gamma", "qdm_prior") with elements shape and rate.

Details

The prior is equivalent to shape events observed during a total observed time of rate, so small values give a weakly informative prior: prior_gamma(0.1, 1) carries the information of a tenth of an event.

See also

Other priors: prior_beta(), prior_dirichlet(), prior_niw(), prior_nix(), prior_vague()

Examples

prior_gamma(0.1, 1)
#> Prior: Gamma(shape = 0.1, rate = 1)