This article, authored by Linda Darling-Hammond from Stanford University, examines the relationship between teacher qualifications and student achievement across states in the United States. Using data from a 50-state survey, state case studies, the 1993-94 Schools and Staffing Surveys (SASS), and the National Assessment of Educational Progress (NAEP), the study finds that teacher preparation and certification are strong correlates of student achievement in reading and mathematics, both before and after controlling for student poverty and language status. The analysis suggests that policies regarding teacher education, licensing, hiring, and professional development significantly impact the qualifications and capacities of teachers. The implications for state efforts to enhance quality and equity in public education are discussed, highlighting the importance of investing in teacher quality. The article also reviews previous research on the factors influencing teacher effectiveness and student learning, noting that while some variables like subject matter knowledge and teaching experience have shown mixed results, teacher preparation and certification are consistently strong predictors of student achievement.This article, authored by Linda Darling-Hammond from Stanford University, examines the relationship between teacher qualifications and student achievement across states in the United States. Using data from a 50-state survey, state case studies, the 1993-94 Schools and Staffing Surveys (SASS), and the National Assessment of Educational Progress (NAEP), the study finds that teacher preparation and certification are strong correlates of student achievement in reading and mathematics, both before and after controlling for student poverty and language status. The analysis suggests that policies regarding teacher education, licensing, hiring, and professional development significantly impact the qualifications and capacities of teachers. The implications for state efforts to enhance quality and equity in public education are discussed, highlighting the importance of investing in teacher quality. The article also reviews previous research on the factors influencing teacher effectiveness and student learning, noting that while some variables like subject matter knowledge and teaching experience have shown mixed results, teacher preparation and certification are consistently strong predictors of student achievement.