"About half of all new teachers leave the profession after just five years on the job." It is a neat and memorable statistic that has been repeatedly cited by news reporters, advocacy groups, union officials, and state education departments, among others. Trouble is, it is arguable and often used misleadingly. Richard M. Ingersoll, the University of Pennsylvania professor whose calculation was first rounded up to the "half" figure in a 2003 report, sticks to upwards of 40 percent. Other scholars, such as Linda Darling-Hammond, an education professor at Stanford University, say the most defensible estimate is about a third. However, new studies of state rather than national retention suggest even a third might be high. In addition, the figure is rarely presented in context, often because it is being used to incite alarm. Most worrisome about the 50 percent figure, though, may be the way it obscures the damage done to some schools--typically those serving poor and minority children--from teachers' switching schools. Broad-brush, statewide strategies to reduce attrition are not the answer to raising teacher quality. Targeted, school-by-school approaches that involve teachers, parents, and principals are needed to create more positive school environments that are more conducive to teaching and learning.