crosscutplot {DOS2} R Documentation

## Scatterplot Associated with the Cross-Cut Test

### Description

A scatterplot of y against x, with the points used by the cross-cut test in black, and the remaining points in grey. See Figure 19.2 in "Design of Observational Studies", second edition.

### Usage

```crosscutplot(x, y, ct = 0.25, xlab = "", ylab = "", main = "", ylim = NULL)
```

### Arguments

 `x` Variable to be plotted on the horizontal axis. `y` Variable to be plotted on the vertical axis. `ct` The quantile that defines the crosscut. By default, the crosscut is at the outer .25 of the data, the lower 25 percent and the upper 75 percent. `xlab` Label for the x axis. `ylab` Label for the y axis. `main` Title of the plot. `ylim` Limits for the y axis. See example.

A scatter plot.

### Author(s)

Paul R. Rosenbaum

### References

Rosenbaum, P. R. (2016) <doi:10.1111/biom.12373> "The crosscut statistic and its sensitivity to bias in observational studies with ordered doses of treatment". Biometrics, 72(1), 175-183.

Rosenbaum, P. R. (2017) <doi:10.1214/17-STS621> "The general structure of evidence factors in observational studies". Statistical Science 32, 514-530.

### Examples

```# Figure 1 in Rosenbaum (2017)
data(periodontal)
attach(periodontal)
m<-matrix(1:2,1,2)
layout(m,widths=c(1,2))
boxplot(pcteither[z==1]-pcteither[z==0],ylab="Smoker-Control Difference",
main="(i)",xlab="Matched Pairs",ylim=c(-100,100))
abline(h=0,lty=2)
crosscutplot(cigsperday[z==1],pcteither[z==1]-pcteither[z==0],
ct=.2,ylab="Smoker-Control Difference",
xlab="Cigarettes per Day",main="(ii)",ylim=c(-100,100))
abline(h=0,lty=2)
detach(periodontal)
layout(1)
```

[Package DOS2 version 0.5.2 Index]