Of all the factors that schools control, teacher quality is the one that most affects student achievement (Darling-Hammond, 2000). In fact, researcher Eric Hanushek (2002) found the difference in annual student achievement growth between a student taught by an effective teacher and one taught by an ineffective teacher can be as much as one grade-level equivalent. The results are cumulative; the impact of an effective teacher on a student's achievement is still measurable two years later regardless of the effectiveness of the intervening teachers. This month's newsletter offers specific suggestions for school and district leaders to consider during the teacher hiring season. While such hiring drives can be difficult and time consuming, improving the instructional capacity of a school may be the most important academic reform a school can undertake. [This document was produced by The Center for Comprehensive School Reform and Improvement, administered by Learning Point Associates in partnership with the Southwest Educational Development Laboratory (SEDL) and WestEd, under contract with the Office of Elementary and Secondary Education of the U.S. Department of Education.]