A meta-analysis of the literature findings on student evaluations of teaching are described. This research supports the validity of student ratings as measures of teaching effectiveness. Teachers whose students do well on achievement measures tend to receive higher instructional ratings than teachers whose students do poorly. Correlational effect sizes for the Skill and Structure dimensions were large; other rating dimensions, such as Rapport, Feedback, and Interaction, did not relate as well to student achievement. Correlational effect sizes for courses were remarkably stable under a variety of study conditions and methodological manipulations. These findings demonstrate that the relationship between ratings and achievement is stronger and more consistent than was previously thought. The advantages of meta-analytic techniques over traditional research reviews are discussed. (Author/PN)