Line drawings of point and interval estimates

Description

Adds one or more points and lines to a plot, representing point and interval estimates.

Usage

1
2
cistrip(x, at, d, horiz=TRUE, pch = 16, cex = 1, lattice=FALSE, ...)
panel.cistrip(...)

Arguments

x

Either a vector of three elements corresponding to point estimate, lower limit and upper limit of the interval estimate, respectively, or a numeric matrix or data frame with three columns representing point estimates, lower and upper limits.

at

Position of the line on the y-axis (if horiz=TRUE) or the x-axis (if horiz=FALSE).

d

Length of the serifs at each end of the line. Defaults to 1/60 of the axis range.

horiz

Draw the line horizontally (TRUE) or vertically (FALSE).

pch

Character to draw at the point estimate, see points. By default this is a small solid circle, pch=16.

cex

Expansion factor for the character at the point estimate, for. A vector can be supplied here, one for each estimate, as in pch. Useful for meta-analysis forest plots.

lattice

Set this to TRUE to make cistrip a lattice panel function instead of a base graphics function.
panel.cistrip(x,...) is equivalent to cistrip(x, lattice=TRUE, ...).

...

Further arguments passed to the points and segments functions or their lattice equivalents. For example lty,lwd to set the style and thickness of the line.

Author(s)

Christopher Jackson <chris.jackson@mrc-bsu.cam.ac.uk>

See Also

denstrip, vwstrip, bpstrip

Examples

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
## One estimate 
x <- c(0.1, -2, 2)
plot(0, type="n", xlim=c(-5, 5), ylim=c(-5, 5), xlab="", ylab="")
abline(h=0, lty=2, col="lightgray")
abline(v=0, lty=2, col="lightgray")
cistrip(x, at=-0.1)
cistrip(x, at=0.2, lwd=3, d=0.1)
cistrip(x, at=-4, horiz=FALSE, lwd=3, d=0.2)

## Double / triple the area of the central point, as in forest plots
cistrip(x, at=2, d=0.2, pch=22, bg="black")
cistrip(x, at=2.5, d=0.2, pch=22, bg="black", cex=sqrt(2))
cistrip(x, at=3, d=0.2, pch=22, bg="black", cex=sqrt(3))

## Several estimates
x <- rbind(c(0.1, -2, 2), c(1, -1, 2.3),
           c(-0.2, -0.8, 0.4), c(-0.3, -1.2, 1.5))
plot(0, type="n", xlim=c(-5, 5), ylim=c(-5, 5), xlab="", ylab="")
cistrip(x, at=1:4)
abline(v=0, lty=2, col="lightgray")
cistrip(x, at=1:4, horiz=FALSE, lwd=3, d=0.2)
abline(h=0, lty=2, col="lightgray")