Sum of direct and indirect effects from dynamic path analysis

a sum method for class "effect"

Usage

# S3 method for class 'effect'
sum(effect1, effect2, ...)

Arguments

effect1: an object of class "effect" obtained from a call to the function effect()
effect2: a second object of class "effect" obtained from a call to the function effect()
...: additional objects of class "effect" (any number of effects allowed)

Value

an object of class "effect" containing the sum of effect1, effect2, ...

Examples

library(dpasurv)

data(simdata)

set.seed(1)

# Perform dynamic path analysis:
# We set boot.n=30 for the example to run fast, should be set large enough
# so that results don't change meaningfully for different seeds.
s <- dpa(Surv(start,stop,event)~M+x, list(M~x), id="subject", data=simdata, boot.n=30)

direct <- effect(x ~ outcome, s)
indirect <- effect(x ~ M ~ outcome, s)
total <- sum(direct, indirect)