Follow-up Plot {epicalc}R Documentation

Longitudinal followup plot

Description

Plot longitudinal values of individuals with or without stratification

Usage

followup.plot(id, time, outcome, by = NULL, n.of.lines = NULL, legend = TRUE, 
    legend.site = "topright", lty = "auto", line.col = "auto", 
    stress = NULL, stress.labels = FALSE, label.col = 1, stress.col = NULL, 
    stress.width = NULL, stress.type = NULL, lwd = 1, xlab, ylab, ...) 

Arguments

id idenfication variable of the same subject being followed up
time time at each measurement
outcome continuous outcome variable
by stratification factor (if any)
n.of.lines number of lines (or number of subjects in the data frame) randomly chosen for drawing
legend whether a legend will be automatically included in the graph
legend.site a single character string indicating location of the legend. See details of ?legend
lty type of the "time" lines. See 'lty' in ?par
line.col line colour(s) for non-stratified plot
stress subset of ids to draw stressed lines
stress.labels whether the stressed lines should be labelled
label.col single integer indicating colour of the stressed line labels
stress.col colour values used for the stressed line. Default value is '1' or black
stress.width relative width of the stressed line
stress.type line type code for the stressed line
lwd line width
xlab label for X axis
ylab label for Y axis
... other graphic parameters

Details

'followup.plot' plots outcome over time of the individual subjects.

If a stratification variable 'by' is specified, the levels of this variable will be used to color the lines.

'n.of.lines' is used to reduce the number of lines to allow the pattern to be seen more clearly.

'legend' is omitted if 'n.of.lines' is not NULL or the number of subjects exceeds 7 without stratification.

'line.col' works only for a non-stratified plot. It can be a single standard colour or "multicolor".

Values for 'stress.col', 'stress.width' and 'stress.type', if not NULL, should follow those for 'col', 'lwd' and 'lty', respectively

Author(s)

Virasakdi Chongsuvivatwong <cvirasak@medicine.psu.ac.th>

See Also

'plot','lines'

Examples

use(Indometh)
followup.plot(Subject, time, conc)
followup.plot(Subject, time, conc, lty=1:6, line.col=rep("black",6))

library(MASS)
use(Sitka)
followup.plot(tree, Time, size)
followup.plot(tree, Time, size, line.col = "brown")
followup.plot(tree, Time, size, line.col = "multicolor")
followup.plot(tree, Time, size, n.of.lines=20, line.col = "multicolor")

# Breakdown of color by treatment group
followup.plot(tree, Time, size, by=treat)

# The number of lines reduced to 40
followup.plot(tree, Time, size, by=treat, n.of.lines=40)

# Stress some lines
length(table(tree)) # 79 trees followed up

# Identifying trees that sometimes became smaller
sortBy(tree, Time)
next.tree <- c(tree[-1], NA)
next.size <- c(size[-1], NA)
next.size[tree != next.tree] <- NA
pack()
smaller.trees <- tree[next.size < size] 
followup.plot (tree, Time, size, line.col=5, stress=smaller.trees, 
  stress.col=2, stress.width=2, stress.type=2)
followup.plot (tree, Time, size, line.col=5, stress=smaller.trees, 
  stress.col=2, stress.width=2, stress.type=2, stress.labels=TRUE)

[Package epicalc version 2.10.1.1 Index]