In recent years the demand for new teachers across the nation has risen steeply. Demographic factors (such as the baby boom echo) and legislative policies (such as class size reduction) have resulted in the increased need for new teachers, while promising young graduates are often discouraged from entering the profession by low salaries and poor earnings opportunities. Many districts attempt to fill shortages by hiring non-credentialed teachers, who, if they are interns attending a credentialing program, are considered "highly qualified" under the terms of NCLB. Under-qualified and least-experienced teachers are often assigned the most difficult classes, and tend to be concentrated in special education, urban schools, and in schools serving students who are poor, minorities, and English learners. Factors such as these lead to high rates of attrition among practicing teachers, lending some educators to suggest we have a teacher retention problem rather than a teacher shortage problem.
High attrition rates have negative effects on student achievement. This is exacerbated by the fact that schools with large numbers of poor and minority pupils have more trouble retaining teachers and the most difficulty attracting new applicants for teaching positions. The continual flight of teachers from these schools creates burdensome extra costs to the district. Hiring and professional development are direct costs, increased instability in the school culture represents an indirect cost.