Using unique administrative data from North Carolina that allow us to separate classroom teacher turnover during the school year from end-of-year turnover, we find students who lose their teacher during the school year have significantly lower test score gains (on average −7.5 percent of a standard deviation unit) than those students whose teachers stay. Moreover, the turnover of other teachers during the year lowers achievement gains, whereas end-of-year teacher turnover appears to have little effect on achievement. The harmful effects of within-year turnover cannot be explained by other extraneous shocks or the quality of departing teachers. Teachers who depart from December through April have the most harmful effects on achievement, although these vary somewhat by level of schooling and subject.

State policies affect the qualifications of beginning teachers in numerous ways, including regulating entry requirements, providing incentives for graduate degrees, and subsidizing preparation programs at public universities. In this paper we assess how these policy choices affect student achievement, specifically comparing traditionally prepared with alternative-entry teachers; in-state traditionally prepared with out-of-state traditionally prepared teachers; teachers beginning with undergraduate degrees with those beginning with graduate degrees; and teachers prepared at in-state public universities with those prepared at in-state private universities. Using school fixed effects to analyze data from North Carolina, we find that: Teach For America corps members are more effective than traditionally prepared teachers; other alternative-entry teachers are less effective than traditionally prepared instructors in high school mathematics and science courses; and out-of-state traditionally prepared teachers are less effective than in-state traditionally prepared teachers, especially in elementary subjects where they constitute nearly 40 percent of the workforce.

To address gaps in achievement between more- and less-affluent students, states and districts need to ensure that high-poverty students and schools have equitable access to educational resources. Traditionally, assessments of resource equity have focused on per-pupil expenditures and more proximal inputs, such as teacher credentials and class size, despite the inconsistent and/or weak relationships between these measures and student performance. Given the sizable and direct effects of teachers on student achievement, we argue that (1) teachers’ value-added scores should be incorporated into assessments of resource equity and (2) providing schools with greater flexibility for setting salaries or using strategic staffing initiatives may be necessary to achieve an equitable distribution of effective teachers. To illustrate these assertions we incorporate teacher value added into a case study of resource allocation in the public high schools of Wayne County, North Carolina, which have been the target of a complaint by the North Carolina National Association for the Advancement of Colored People.