Studies m Educahonal Evaluation. Vol. 21, pp. 41 l-429, 1995 0 1995 Elsetier Science LM Printed in Great Britain. All rights reserved. 0191-491x/95$29.00 0191-491x(95)00023-2 STUDENTS’ RATINGS OF INSTRUCTION: GENERALIZABILITY OF FINDINGS Karma El-Hassan Division of Education Programs, American University of Beirut, Beirut, Lebanon Students’ ratings of instruction are widely used in universities and colleges as they serve a variety of important practical purposes. They provide (a) diagnostic feedback to faculty about the effectiveness of their teaching, (b) a measure of teaching effectiveness to be used in tenure/promotion decisions, (c) information for students to use in the selection of courses and instructors, and (d) an outcome on a process description for research or teaching; that is, they could answer questions like How do teachers behave? Why do they behave as they do? And what are the effects of their behavior? (Gage, 1972, as cited in Marsh 1984; Marsh, 1984). Students’ evaluations have been extensively studied in education. Cashin (1988) lists more than 1300 articles and books related to students’ ratings. These studies have been characterized as being (a) extensive, (b) contradictory and (c) of highly variable quality (Dowel1 & Neal, 1982). Most of this research deals with the dimensionality, validity, reliability and generalizability of students’ ratings of instruction and the investigation of the potentially ” biasing ” factors that could affect the validity of these ratings. The debate over the dimensionality of teaching and, subsequently, of student ratings of instruction has been the subject of several studies (Abrami, 1985, 1988; Cashin, 1988; Feldman, 1976; Frey, 1978; Marsh, 1987). Some investigators believe that teaching effectiveness is multidimensional; that is, it is composed of several specific factors and subsequently no single student item or set of items can serve all purposes. Others believe in the unidimensionality of teaching and argue for a large homogeneous general trait underlying all “effective teaching”. Recent research reviews on the matter have settled 411