Introduction

Cronbach, L. J. "The Two Disciplines of Scientific Psychology." American Psychologist, XII (1957), 671-684.

Stanley, J. C. "Interaction of Organisms with Experimental Variables as a Key to the Integration of Organismic and Variable-Manipulating Research." 17th Yearbook of the National Council on Measurement in Education ( Edith M. Huddleston , Editor), 1960, 7-13. Ames, Iowa: Dr. W. L. Layton, Secretary-Treasurer, NCME, Department of Psychology, Iowa State University.

Stanley, J. C. "Studying Status Versus Manipulating Variables." Chapter VI (pp. 173-208) in Collier, R. O., Jr. and Elam, S. M. (Editors), "Research Design and Analysis," the Second Annual Phi Delta Kappa Symposium on Educational Research. Bloomington, Indiana: Phi Delta Kappa, 1961.