A discussion and illustration of multivariate aspects of the Varient/WABA approach for multi-level theory testing are presented. After a consideration of univariate and bivariate conceptual and empirical issues, multiple variable analysis (MVA) and multiple relationship analysis (MRA) are examined from theoretical, methodological, and illustrative perspectives. A brief review of multivariate WABA using hierarchical linear multiple regression, and a general discussion of the Varient/WABA approach in comparison to other multi-level approaches, also are presented.