摘要
Objective: Information about immunization coverage comes from five major sources: the National Immunization Survey, the National Health Interview Survey, retrospective school-entry surveys, the Health Plan Employer Data and Information Set (HEDIS) measures reported by managed care plans, and assessments performed on clinics and private practices. In this article, we describe the methodology of the major surveys, discuss technical and policy issues in measuring immunization coverage, and identify issues that must be addressed to harmonize immunization rates calculated from different sources.