Syntax: ROBUSTREG Procedure

The following statements are available in PROC ROBUSTREG:

PROC ROBUSTREG <options> ;

BY variables ;

CLASS variables ;

ID variables ;

MODEL response=<effects> </ options> ;

OUTPUT <OUT=SAS-data-set> <options> ;

PERFORMANCE <options> ;

TEST effects ;

WEIGHT variable ;

The PROC ROBUSTREG statement invokes the procedure. The METHOD= option in the PROC ROBUSTREG statement selects one of the four estimation methods, M, LTS, S, and MM. By default, Huber M estimation is used. The MODEL statement is required and specifies the variables used in the regression. Main effects and interaction terms can be specified in the MODEL statement, as in the GLM procedure ( Chapter 39, The GLM Procedure. ) The CLASS statement specifies which explanatory variables are treated as categorical. These variables are allowed in the MODEL statement only for M estimation and not for other estimation methods. The ID statement names variables to identify observations in the outlier diagnostics tables. The WEIGHT statement identifies a variable in the input data set whose values are used to weight the observations. The OUTPUT statement creates an output data set containing final weights, predicted values, and residuals. The TEST statement requests robust linear tests for the model parameters. The PERFORMANCE statement tunes the performance of the procedure by using single or multiple processors available on the hardware. In one invocation of PROC ROBUSTREG, multiple OUTPUT and TEST statements are allowed.