In order to explore the effects of student ratings as feedback for faculty, and to test a large scale system for evaluating faculty's teaching performance by students, 2,195 college students completed the Questionnaire of Teaching Activities ''CAD'' on the teaching performance of seventy faculty members in as many regularly scheduled academic sections, The design and construction of the questionnaire followed rigurous psychometric and scaling standards during validation and reliability assessment. The implementation of procedures to evaluate the effects of providing feedback to the faculty from detailed student ratings, took special care to prevent confounding factors such as artificially inducing responses to students, among other contaminants typical of this type of studies. Results showed that the evaluation system is useful, practical and reliable in assessing large scale academic systems, including the analysis of such factors as faculty seniority, and that the feedback procedure was successful in improving several teacher efficiency indicators.