A growing body of research evaluates the effects of turnaround on chronically low-performing schools. We extend this literature by formally testing factors that may either mediate or suppress the effects of two turnaround initiatives in Tennessee: the Achievement School District (ASD) and local Innovation Zones (iZones). Using difference-in-differences models within a mediational framework, we find that hiring effective teachers and principals partially explains positive iZone effects. In the ASD, high levels of teacher turnover suppress potential positive effects. Also, in iZone schools, increased levels of student mobility and chronic absenteeism suppress potentially larger positive effects. Policies that increase capacity within turnaround schools, such as financial incentives for effective staff, appear to be important ingredients for realizing positive effects from turnaround reforms.

中文翻译：

---

窥视学校周转的黑匣子：冥想者和抑制者的正式考验

越来越多的研究评估了周转对长期表现欠佳的学校的影响。我们通过正式测试可能介导或抑制田纳西州两个转变举措的影响的因素来扩展该文献，这些成就是学区（ASD）和地方创新区（iZones）。使用中介框架中的差异模型，我们发现雇用有效的教师和校长可以部分解释iZone的积极影响。在ASD中，高水平的教师离职会抑制潜在的积极影响。另外，在iZone学校中，学生活动水平的提高和长期缺勤会抑制潜在的较大正面影响。旨在提高周转学校能力的政策，例如对有效员工的财务激励措施，