tvc: Create a time interaction variable

In christophergandrud/simtvc: Tools for simulating and graphing time-varying hazards.

Description

tvc creates a time interaction variable that can be used in a coxph model (or any other model with time interactions)

Usage

  tvc(data, b, tvar, tfun = "linear", pow = NULL)

Arguments

data	a data frame
b	the non-time interacted variable's name
tvar	the time variable's name
tfun	function of time that btvc was multiplied by. Default is tfun = "linear". Can also be tfun = "log" (natural log) and tfun = "power". If tfun = "power" then the pow argument needs to be specified also.
pow	if tfun = "power", then use pow to specify what power to raise the time interaction to.

Details

Interacts a variable with a specified function of time. Possible functions of time include 'linear', natural 'log', and exponentiated ('power').

Value

a vector

See Also

ggtvc, coxsimtvc, survival, and coxph

Examples

# Load Golub & Steunenberg (2007) Data
data("GolubEUPData")

# Create natural log time interaction with the qmv variable
GolubEUPData$Lqmv <- tvc(GolubEUPData, b = "qmv", tvar = "end", tfun = "log")

christophergandrud/simtvc documentation built on May 13, 2019, 7:03 p.m.