In this volume, Shavelson and Webb offer an intuitive development of generalizability theory and cover a wide variety of topics such as generalizability studies with nested facets and with fixed facets, measurement error and generalizability coefficients, and decision studies with same and with different designs. Detailed illustrations, examples and exercises all serve to clearly describe the logic underlying major concepts in generalizability theory and assist readers in applying these methods when investigating the consistency of their own measurements.