SAS Macro Programs: inflogis

The inflogis macro ( get inflogis.sas)

Influence plots for logistic regression

Method

Usage

The arguments may be listed within parentheses in any order, separated by commas. For example:

  %include data(arthrit);
  %inflogis(data=arthrit,
        y=better,
        x=_sex_ _treat_ age,
        id=case,
        );

Parameters

DATA=

Specifies the name of the input data set to be analyzed. [Default: DATA=_LAST_]

Y=

Name of the response variable

TRIALS=

Name of trials variable (for event/trials syntax)

X=

Names of predictors

CLASS=

Names of class variables among predictors (V8)

ID=

Name of observation ID variable (char)

OUT=

Name of the output data set [Default: OUT=_DIAG_]

GY=

Ordinate for plot: DIFDEV or DIFCHISQ [Default: GY=DIFDEV]

GX=

Abscissa for plot: PRED or HAT [Default: GX=PRED]

BUBBLE=

Bubble proportional to: C or CBAR [Default: BUBBLE=C]

LABEL=

Points to label: ALL, NONE, or INFL [Default: LABEL=INFL]

DEV=

DIFDEV/DIFCHISQ criterion for infl pts [Default: DEV=4]

INFL=

Specifies the criterion used to determine which observations are influential (when used with LABEL=INFL). [Default: INFL=%STR(DIFCHISQ > &DEV OR &BUBBLE > 1)]

LSIZE=

Observation label size. The height of other text is controlled by the HTEXT= goption. [Default: LSIZE=1.5]

LCOLOR=

Observation label color [Default: LCOLOR=BLACK]

LPOS=

Observation label position [Default: LPOS=5]

LFONT=

Font used for observation labels.

BSIZE=

Bubble size scale factor [Default: BSIZE=10]

BSCALE=

Bubble size proportional to AREA or RADIUS [Default: BSCALE=AREA]

BCOLOR=

Bubble color [Default: BCOLOR=BLACK]

BFILL=

Bubble fill? Options are BFILL=SOLID | GRADIENT, where the latter uses a gradient version of BCOLOR

REFCOL=

Color of reference lines [Default: REFCOL=BLACK]

REFLIN=

Line style for reference lines; 0->NONE [Default: REFLIN=33]

LOPTIONS=

Options for PROC LOGISTIC [Default: LOPTIONS=NOPRINT]

NAME=

Name of the graph in the graphic catalog [Default: NAME=INFLOGIS]

GOUT=

Name of the graphics catalog

Example

The plots display the Chi-square difference when the observation is deleted vs. both thepredicted probability of succesful outcome and the leverage with the bubble size proportional to the Cook's D measure of influence.

%include macros(inflogis);        *-- or include in an autocall library;
%include data(arthrit);

%inflogis(data=arthrit,
     y=better,
     x=_sex_ _treat_ age,
     id=case,
     gy=DIFCHISQ,
     gx=PRED HAT,
     lcolor=RED, bsize=14
     );

See also