The GLM procedure is the flagship tool for classical analysis of variance in SAS/STAT software. It performs analysis of variance by using least squares regression to fit general linear models. Among the statistical methods available in PROC GLM are regression, analysis of variance, analysis of covariance, multivariate analysis of variance, repeated measures analysis, and partial correlation analysis.

While PROC GLM can handle most common analysis of variance problems, other procedures are more efficient or have more features than PROC GLM for certain specialized analyses, or they can handle specialized models that PROC GLM cannot. Much of the rest of this chapter is concerned with comparing PROC GLM to other procedures.