Contents: Preface. Introduction. Part I: Historical and Epistemological Bases of Validity.L.J. Cronbach, Five Perspectives on the Validity Argument. W.H. Angoff, Validity: An Evolving Concept. S. Messick, The Once and Future Issues of Validity: Assessing the Meaning and Consequences of Measurement. Part II: The Changing Faces of Validity.J.W. Pellegrino, Mental Models and Mental Tests. R.J. Sternberg, GENECES: A Rationale for the Construct Validation of Theories and Tests of Intelligence. B.F. Green, Construct Validity of Computer-Based Tests. Part III: Testing Validity in Specific Subpopulations.W.W. Willingham, Testing Handicapped People -- The Validity Issue. R.P. Dura'n, Validity and Language Skills Assessment: Non-English Background Students. P.W. Holland, D.T. Thayer, Differential Item Performance and the Mantel-Haenszel Procedure. D. Thissen, L. Steinberg, H. Wainer, Use of Item Response Theory in the Study of Group Differences in Trace Lines. Part IV: Statistical Innovations in Validity Assessment.F.L. Schmidt, Validity Generalization and the Future of Criterion-Related Validity. L.V. Hedges, The Meta-Analysis of Test Validity Studies: Some New Approaches. B. Muthe'n, Some Uses of Structural Equation Modeling in Validity Studies: Extending IRT to External Variables. D.B. Rubin, Discussion.