catplot Plots for logit models fit by PROC CATMOD catplot

Visualizing Categorical Data: catplot

$Version: 1.4 (9 Nov 2000)
Michael Friendly
York University


The catplot macro ( [download] get catplot.sas)

Plots for logit models fit by PROC CATMOD

The catplot macro is designed to plot observed and/or predicted values for logit models fit by the CATMOD procedure. The macro uses the output data set produced with the OUT= option on the RESPONSE statement. This data set normally contains both logit values (_type_='FUNCTION') and probability values (_type_='PROB'). Either set may be plotted, as specified by the TYPE= parameter.

The horizontal variable may be character (XC=) or numeric (X=). A separate curve is drawn for each value of the CLASS= variable, connecting predicted values, with optional standard error bars, and separate plots are drawn for each value of the BYVAR= variable.

Usage

The catplot macro is called with keyword parameters. The arguments may be listed within parentheses in any order, separated by commas. For example:

 proc catmod;
        direct husinc;
        response / out=logits;
        model labour = husinc children; 
 %catplot(data=logits, x=husinc, y=_pred_, class=labor, byvar=children);

Parameters

DATA=
The name of the SAS dataset to be plotted, which must be an output data set from PROC CATMOD. If DATA= is not specified, the most recently created data set is used.
X=
Name of a numeric factor variable to be used as the horizontal variable in plots. Use the XC= parameter to specify a character variable. You must specify either the X= or XC= variable.
XC=
Name of a character factor variable used as the horizontal variable in plots.
Y=
Name of the ordinate variable. Y=_PRED_ plots the predicted value; Y=_OBS_ plots the observed value.
CLASS=
The name of a factor variable, used to define separate curves which are plotted for each level of this variable.
BYVAR=
Name of one or more factor variables to be used to define multiple panels in plots.
BYFMT=
Name of a SAS format used to format the value of BYVARs for display in one panel of the plot(s).
TYPE=
The type of oobservations to be plotted. TYPE=FUNCTION (the default) gives plots of the logit value; TYPE=PROB gives plots of the probability value.
Z=
Standard error multiple for confidence intervals around predicted values, e.g., Z=1.96 gives 95% CI. To suppress error bars, use Z=0. The default is Z=1, giving 67% CI.
CLFMT=
Name of a SAS format used to format the value the CLASS= variable for display in each panel of the plot(s).
CLSIDE=
Specifies whether the values of the CLASS= variable should be labelled by annotation in the plot or by a legend. If CLSIDE=LEFT or CLSIDE=FIRST, CLASS= values are written at the left side of each curve. If CLSIDE=RIGHT or CLSIDE=LAST, CLASS= values are written at the right side of each curve. If CLSIDE=NONE, CLASS= values appear in the legend.
XFMT=
Name of a SAS format used to format the values of the horizontal variable.
ANNO=
Name of an additional input annotate data set
SYMBOLS=
List of SAS/GRAPH symbols for the levels of the CLASS= variable. There should be as many symbols as there are distinct values of the CLASS=variable.
COLORS=
List of SAS/GRAPH colors for the levels of the CLASS= variable. There should be as many colors as there are distinct values of the CLASS= variable.
LINES=
List of SAS/GRAPH line styles for the levels of the CLASS= variable. There should be as many lines as there are distinct values of the CLASS= variable.
HAXIS=
Axis statement for custom horizontal axis, e.g., HAXIS=AXIS2
VAXIS=
Axis statement for custom response axis, e.g., VAXIS=AXIS1. If no axis statement is defined, the program uses AXIS1 LABEL=(a=90).
LEGEND=
Legend statement for custom CLASS legend, e.g., LEGEND=LEGEND1

Example

[None yet]

See also

inflogis Influence plot for logistic regression models
pscale Construct annotations for a probability scale