This article provides a review of recent research on the quality of survey data and serves as an introduction to this special issue of SMR. The article reviews standard statistical treatments of survey errors and discusses the importance of developing population models for measurement errors. A model is presented which nests measurement errors within other nonmeasurement survey errors—errors of coverage, sampling, and nonresponse. Promising new developments in research on survey measurement are reviewed and evaluated—applications of rational choice theories of response behavior, applications of cognitive theories of judgment and information processing, and experiments in the meaning of questions. The article concludes with a brief summary o...