The RSREG procedure fits a quadratic response-surface model, which is useful in searching for factor values that optimize a response. The following features in PROC RSREG make it preferable to other regression procedures for analyzing response surfaces:

• automatic generation of quadratic effects

• a lack-of-fit test

• solutions for critical values of the surface

• eigenvalues of the associated quadratic form

• a ridge analysis to search for the direction of optimum response