calc_rmd {psm3mkv} | R Documentation |
Calculate restricted mean durations
Description
Calculates the restricted mean duration, given the form of a parametric distribution of Royston-Parmar splines
Usage
calc_rmd(Tw, type = NA, spec = NA, survobj = NULL)
Arguments
Tw |
is the time horizon (weeks) over which the mean should be calculated.
|
type |
is either "par" for regular parametric form (exponential, weibull etc) or "spl" for Royston-Parmar splines.
|
spec |
is a list comprising:
If type=="par": dist is the statistical distribution (named per flexsurv::flexsurvreg) and pars is a vector of the parameters for that distribution.
Exponential distribution (exp ) requires the rate parameter.
Weibull distribution (both weibullPH and weibull formulations) requires the shape and scale parameters.
Log-logistic distribution (llogis ) requires the shape and scale parameters.
Log-normal distribution (lnorm ) requires the meanlog and sdlog parameters.
Gamma and Gompertz distributions (gamma and gompertz ) require the shape and rate parameters.
Generalized Gamma requires the mu, sigma and Q parameters if using the standard parameterization (gengamma ) or shape, scale and k parameters if using the original parameterization (gengamma.orig ).
If type=="spl":
-
gamma - Vector of parameters describing the baseline spline function, as described in flexsurv::flexsurvspline. This may be supplied as a vector with number of elements equal to the length of knots, in which case the parameters are common to all times. Alternatively a matrix may be supplied, with rows corresponding to different times, and columns corresponding to knots.
-
knots - Vector of locations of knots on the axis of log time, supplied in increasing order. Unlike in flexsurv::flexsurvspline, these include the two boundary knots.
-
scale - Either "hazard", "odds", or "normal", as described in flexsurv::flexsurvspline. With the default of no knots in addition to the boundaries, this model reduces to the Weibull, log-logistic and log-normal respectively. The scale must be common to all times.
|
survobj |
is a survival fit object from flexsurv::flexsurvspline or flexsurv::flexsurvreg
|
Value
the restricted mean duration, a numeric value.
Examples
calc_rmd(Tw=200,
type="spl",
spec=list(gamma=c(0.1,0.2,0.1), knots=c(-5,2,4), scale="normal")
)
calc_rmd(Tw=250,
type="par",
spec=list(dist="lnorm", pars=c(3,1))
)
[Package
psm3mkv version 0.3.2
Index]