SurvExpand: Convert a data frame of non-equal interval continuous observations into equal interval continuous observations

Description

SurvExpand convert a data frame of non-equal interval continuous observations into equal interval continuous observations. This is useful for creating time-interactions with tvc.

Usage

SurvExpand(data, GroupVar, Time, Time2, event, PartialData = TRUE,
  messages = TRUE)

Arguments

data

a data frame.

GroupVar

a character string naming the unit grouping variable.

Time

a character string naming the variable with the interval start time.

Time2

a character string naming the variable with the interval end time.

event

a character string naming the event variable. Note: must be numeric with 0 indicating no event.

PartialData

logical indicating whether or not to keep only the expanded data required to find the Cox partial likelihood.

messages

logical indicating if you want messages returned while the function is working.

Value

Returns a data frame where observations have been expanded into equally spaced time intervals.

Details

The function primarily prepares data from the creation of accurate time-interactions with the tvc command. Note: the function will work best if your original time intervals are recorded in whole numbers. It also currently does not support repeated events data.

Examples

Run this code

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

# Subset PURELY TO SPEED UP THE EXAMPLE
GolubEUPData <- GolubEUPData[1:500, ]

# Expand data
GolubEUPDataExpand <- SurvExpand(GolubEUPData, GroupVar = 'caseno',
                       Time = 'begin', Time2 = 'end', event = 'event')