Why are preschool programs becoming less effective?
本文探讨了现代学前教育项目效果弱于20世纪中期示范项目的原因，认为主要在于未入学儿童早期条件改善，而非后续学校教育质量差，并呼吁通过严谨的纵向研究提升项目有效性。
Abstract Public preschool programs are heralded as an effective policy tool for promoting the development and lifelong well‐being of children from low‐income families. Recent preschool evaluations report divergent findings that are consistently weaker than those of famous demonstration programs implemented in the mid‐20th century. We provide potential explanations for these weaker effects, the most compelling of which focuses on improvements in the early childhood conditions of children not enrolling in public programs. We argue that other explanations, such as subsequent low‐quality schooling experiences, do not convincingly account for weakening program effectiveness. We do not contest whether governments should invest in effective care for young children. Rather, we focus on the current state of the evaluation evidence for programs at scale. We argue the field must take seriously the disappointing impacts of modern programs on child outcomes and strive to understand how to boost program effectiveness through rigorous, longitudinal research.