In her testimony presented before the District of Columbia City Council, the author makes three points. These are: (1) Teachers matter; (2) The variation in teacher effectiveness is greater within schools than the variation between schools; and the variation within schools serving students from the poorest backgrounds is greater than the variation within schools serving more advantaged students; and (3) The variation in teacher effectiveness, both within and between schools, is a "management problem that begs for attention." She offers key points of intervention. The first is recruitment/hiring. A second point of intervention is when teachers are on the job. There are two strategies, all based on how well a teacher is performing on the job. One is the point of tenure and the other is evaluation of ongoing performance. (Contains 1 footnote.)