Studies in Higher Education Vol. 30, No. 6, December 2005, pp. 723–748 ISSN 0307-5079 (print)/ISSN 1470-174X (online)/05/060723–26 © 2005 Society for Research into Higher Education DOI: 10.1080/03075070500340101 The dimensionality of student ratings of teaching: integration of uni- and multidimensional models Pedro Apodaca a * and Hector Grad b a Universidad País Vasco, Spain; b Universidad Autónoma de Madrid, Spain Taylor and Francis Ltd CSHE_A_133993.sgm 10.1080/03075070500340101 Studies in Higher Education 0307-5079 (print)/1470-174X (online) Original Article 2005 Taylor & Francis 30 6 000000December 2005 PedroApodaca Instituto de Ciencias de la EducaciónUniversidad del País Vasco48940 Leioa (Bizkaia)Spainplpapurp@lg.ehu.es The debate on the unidimensionality versus multidimensionality of students’ ratings of teaching performance, and the relationship of this dilemma to summative and formative uses of these instru- ments is reviewed, with special attention to the implications of their development and application in the Spanish university system. A comprehensive theoretical framework, stressing the relation between effective teaching theory and the expected construct of teaching performance in students’ view, is advanced. The structure of teaching competencies is analysed by means of confirmatory factor analysis (CFA) and similarity structure analysis (SSA) in two ratings forms, of 13 and 34 items. The forms were applied to large student samples from two Spanish universities, rating the performance of individual teachers. CFA and SSA show a common latent structure in the two samples, and support the conceptual distinction between aspects of teaching competence. The results suggest that the structure of the students’ ratings can be interpreted as multidimensional as much as unidimensional. The reason for this apparent paradox is that some specific dimensions are more central (versus peripheral) in the construct of teaching skills. This structure is consistent with the conceptual framework, and would explain the ambiguity between unidimensional and multidi- mensional solutions of CFA outcomes. The implications of these results for the orientation of future research on the dimensionality of students’ ratings and for their application in formative and summa- tive evaluation of teaching are discussed. Introduction Students’ ratings of teaching performance have a comparatively short history in Spain, since they were introduced after the democratization of Spanish universities in the early 1980s. Spanish universities, public in the main, shifted then from an elitist to a democratic model (Quintanilla, 1998). This modernization implied strong teaching and research demands for academic institutions and staff, since it combined * Corresponding author. E. U Magisterio, Universidad Pais Vasco, c/Ramóny Cajal 72, 48014- Bilbao, Spain. Email: pedro.apodaca@ehu.es