Visualizing Categorical Data: mosaic

The mosaic macro ( get mosaic.sas)

Macro interface for mosaic displays

The MOSAIC macro may be used with any SAS data set in frequency form (e.g., the output from PROC FREQ). The macro simply creates the PROC IML step, reads the input data set, and runs the either the mosaic module, the mosaicd module, or the mospart module, depending on the options specified. If your data is in case form, just use PROC FREQ first to construct the contingency table.

Ordinarily, the program fits a model (specified by the FITTYPE= parameter) and displays residuals from this model in the mosaic for each marginal subtable specified by the PLOTS= parameter. However, if you have already fit a model and calculated residuals some other way (e.g., using PROC CATMOD or PROC GENMOD), specify a RESID= variable in the macro call. The macro will then call the mosaicd module.

If a BY= variable is specified, the macro produces one (partial) mosaic plot for each level of the BY variable(s).

Usage

DATA=

Specifies the name of the input dataset. The data set should contain one observation per cell, the variables listed in VAR= and COUNT=, and possibly RESID= and BY=.

VAR=

Specifies the names of the factor variables for the contingency table. Abbreviated variable lists (e.g., V1-V3) are not allowed. The levels of the factor variables may be character or numeric, but are used `as is' in the input data. You may omit the VAR= variables if variable names are used in the VORDER= parameter.

BY=

Specifies the names of one (or more) By variables. Partial mosaic plots are produced for each combination of the levels of the BY= variables. The BY= variable(s) *must* be listed among the VAR= variables.

COUNT=

Specifies the names of the frequency variable in the dataset

CONFIG=

For a user-specified model, CONFIG= gives the terms in the model, separated by '/'. For example, to fit the model of no-three-way association, specify

        config=1 2 / 1 3 / 2 3

or (using variable names)

        config = A B / A C / B C

Note that the numbers refer to the variables after they have been reordered, either sorting the data set, or by the VORDER= parameter.

VORDER=

Specifies either the names of the variables or their indices in the desired order in the mosaic. Note that the using the VORDER parameter keeps the factor levels in their order in the input data set.

SORT=

Specifies whether and how the input data set is to be sorted to produce the desired order of variables in the mosaic. SORT=YES sorts the data in the reverse order that they are listed in the VAR= paraemter, so that the variables are entered in the order given in the VAR= parameter. Otherwise, SORT= lists the variable names, possibly with the DESENDING or NOTSORTED options in the reverse of the desired order. e.g., SORT=C DESCENDING B DESCENDING A. The default is SORT=YES, unless VORDER= has been specified.

RESID=

Specifies that a model has already been fit and that externally calculated residuals are contained in the variable named by the RESID= parameter.

Example

%include vcd(mosaic);        *-- or include in an autocall library;

%mosaic();

See also