R: Data on Back Pain Prognosis, from Anderson (1984)

backPain {VGAM} | R Documentation

## Data on Back Pain Prognosis, from Anderson (1984)

### Description

Data from a study of patients suffering from back pain. Prognostic variables were recorded at presentation and progress was categorised three weeks after treatment.

### Usage

    data(backPain)

### Format

A data frame with 101 observations on the following 4 variables.

x2

  length of previous attack.

x3

  pain change.

x4

  lordosis.

pain

  an ordered factor describing the progress of each patient with levels `worse` < `same` < `slight.improvement` < `moderate.improvement` < `marked.improvement` < `complete.relief`.

### Source

`http://ideas.repec.org/c/boc/bocode/s419001.html`

The data set and this help file was copied from gnm so that a vignette in VGAM could be run; the analysis is described in Yee (2010).

The data frame `backPain2` is a modification of `backPain` where the variables have been renamed (`x1` becomes `x2`, `x2` becomes `x3`, `x3` becomes `x4`) and converted into factors.

### References

Anderson, J. A. (1984). Regression and Ordered Categorical Variables. J. R. Statist. Soc. B, 46(1), 1-30.

Yee, T. W. (2010). The VGAM package for categorical data analysis. Journal of Statistical Software, 32, 1–34. http://www.jstatsoft.org/v32/i10/.

### Examples

    summary(backPain)
    summary(backPain2)

[Package VGAM version 1.1-3 Index]