SurvExpand() R function from [simPH]

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

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.


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.

Returns

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


# 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')

References

Gandrud, Christopher. 2015. simPH: An R Package for Illustrating Estimates from Cox Proportional Hazard Models Including for Interactive and Nonlinear Effects. Journal of Statistical Software. 65(3)1-20.

SurvExpand function