Teacher quality is the school factor which makes the greatest impact on student achievement and consistent exposure to effective teachers can overcome obstacles to learning and even close achievement gaps. These facts were the driving force behind the development of federal law, in the No Child Left Behind Act, mandating that states ensure that 1) teachers of core subjects are "highly qualified" and 2) poor and minority children are not taught at higher rates than other children by inexperienced, unqualified, or out-of-field teachers. The latter provision, known as the teacher equity clause, is an attempt by federal policy to rectify one of the major problems facing low-performing schools that serve large numbers of poor and minority students: the inequitable distribution of teachers. Inequitable distribution is a problem at all grade levels, but some aspects are more pronounced in high schools. Overall, the key to solving distribution problems is to act comprehensively, by significantly increasing the supply of teacher candidates where shortages exist, improving the recruitment and hiring process, and retaining effective teachers in low-performing high schools. Understanding the dynamics of the teacher labor market can ensure that strategies actually impact teachers' decisions concerning where to work and how long they stay. Although states and districts have the most influence over teacher policies, federal law can also help improve the distribution of teachers by supporting and encouraging good recruitment and retention practices at the state and local levels. (Contains 1 footnote.)