time_dependent_cox.r

# Load the survival package
library(survival)

# Read in the CSV
data <- read.csv('C:/users/dbatten/desktop/time_varying_covariate.csv')

# Fit a cox model of a survival object on whether or not the user contacted support
fit <- coxph(Surv(start_time, end_time, churned) ~ contacted_support, data = data)

# Have a gander at the results
summary(fit)

# Make sure we haven't violated the proportional hazards assumption
cox.zph(fit)