defMiss: Definitions for missing data

In kgoldfeld/simstudy: Simulation of Study Data

Definitions for missing data

Description

Add single row to definitions table for missing data

Usage

defMiss(
  dtDefs = NULL,
  varname,
  formula,
  logit.link = FALSE,
  baseline = FALSE,
  monotonic = FALSE
)

Arguments

dtDefs	Definition data.table to be modified
varname	Name of variable with missingness
formula	Formula to describe pattern of missingness
logit.link	Indicator set to TRUE when the probability of missingness is based on a logit model.
baseline	Indicator is set to TRUE if the variable is a baseline measure and should be missing throughout an entire observation period. This is applicable to repeated measures/longitudinal data.
monotonic	Indicator set to TRUE if missingness at time t is followed by missingness at all follow-up times > t.

Value

A data.table named dtName that is an updated data definitions table

See Also

genMiss, genObs

Examples

def1 <- defData(varname = "m", dist = "binary", formula = .5)
def1 <- defData(def1, "u", dist = "binary", formula = .5)
def1 <- defData(def1, "x1", dist = "normal", formula = "20*m + 20*u", variance = 2)
def1 <- defData(def1, "x2", dist = "normal", formula = "20*m + 20*u", variance = 2)
def1 <- defData(def1, "x3", dist = "normal", formula = "20*m + 20*u", variance = 2)

dtAct <- genData(1000, def1)

defM <- defMiss(varname = "x1", formula = .15, logit.link = FALSE)
defM <- defMiss(defM, varname = "x2", formula = ".05 + m * 0.25", logit.link = FALSE)
defM <- defMiss(defM, varname = "x3", formula = ".05 + u * 0.25", logit.link = FALSE)
defM <- defMiss(defM, varname = "u", formula = 1, logit.link = FALSE) # not observed
defM

# Generate missing data matrix

missMat <- genMiss(dtName = dtAct, missDefs = defM, idvars = "id")
missMat

# Generate observed data from actual data and missing data matrix

dtObs <- genObs(dtAct, missMat, idvars = "id")
dtObs

kgoldfeld/simstudy documentation built on April 14, 2024, 3:13 a.m.