The power of an effective teacher and why we should assess it -- How can we assess teacher quality? -- Assessing teacher quality with student work : the Oregon Teacher Work Sample Methodology -- Assessing teacher quality in a standards-based environment : the Thompson, Colorado School District -- Assessing teacher quality through goal-setting : the Alexandria, Virginia School District -- Assessing teacher quality based on student gains : Value-Added Assessment System in Tennessee -- Final thoughts on assessing teacher quality : guidelines for policy and practice.