abacus.plot {IrregLong}

Create an abacus plot Creates an abacus plot, depicting visits per subject over time

Description

Create an abacus plot Creates an abacus plot, depicting visits per subject over time

Usage

abacus.plot(
  n,
  time,
  id,
  data,
  tmin,
  tmax,
  xlab.abacus = "Time",
  ylab.abacus = "Subject",
  pch.abacus = 16,
  col.abacus = 1
)

Arguments

n

the number of subjects to randomly sample. Subjects are sampled without replacement and therefore n must be smaller than the total number of subjects in the dataset

time

character string indicating which column of the data contains the time at which the visit occurred

id

character string indicating which column of the data identifies subjects

data

data frame containing the variables in the model

tmin

the smallest time to include on the x-axis

tmax

the largest time to include on the x-axis

xlab.abacus

the label for the x-axis

ylab.abacus

the label for the y-axis

pch.abacus

the plotting character for the points on the abacus plot

col.abacus

the colour of the rails on the abacus plot

Details

This function creates a plot for n randomly sampled individuals from the supplied dataset, with one row per subject and one point per visit. This can be useful for visualising the extent of irregularity in the visit process. For example, with perfect repeated measures data (i.e., no irregularity), the points will line up vertically. With greater irregularity, the points will be randomly scattered over time.

Value

produces a plot depicting observation times for each subject. No values are returned

Examples

library(MEMSS)
data(Phenobarb)
Phenobarb$event <- 1-as.numeric(is.na(Phenobarb$conc))
data <- Phenobarb[Phenobarb$event==1,]
abacus.plot(n=20,time="time",id="Subject",data=data,tmin=0,tmax=16*24,
xlab.abacus="Time in hours",pch=16,col.abacus=gray(0.8))