THIS PAPER EXAMINES SOME OF THE MEASUREMENT AND EVALUATION PROBLEMS ENCOUNTERED IN RESEARCH ON STUDENT-LED SMALL GROUP DISCUSSION TEACHING PROCEDURES. IT FOCUSES UPON PROBLEMS OF CRITERION EXAMINATION, USE OF RATING FORMS TO ASSESS THE EFFECTIVENESS OF VARIOUS METHODS OF INSTRUCTION, AND METHODS FOR CHARACTERIZING CLASSROOM PROCEDURE. THIS PAPER WAS PRESENTED AT THE AMERICAN PSYCHOLOGICAL ASSOCIATION CONVENTION (NEW YORK CITY, SEPTEMBER 2, 1966). (AUTHOR/DG)