Recent national concerns about student performance on PISA tests and similar assessments appear warranted because of the direct relationship between student cognitive skills and both individual earnings and national growth. The evidence on the impacts of school quality indicates very large economic effects. Available research shows, however, that improving school quality is difficult and not closely related to spending levels. One approach supported by research is improving teacher quality, which can yield sizable gains in student performance. Instituting appropriate policies to alter the teacher force will necessarily take significant time.