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

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. https://www.jstatsoft.org/v32/i10/.

Examples