This is Volume 79, Issue 4 2004 of the Peabody Journal of Education and this special issue provides a collection of works on the topic of Assessing Teacher, Classroom and School Effects in the US. The six articles focus generally on new directions in assessing and measuring teacher, classroom, and school effects on improvements in student academic achievement and more specifically analyze the criterion validity and surrounding human resources strategies of new efforts to implement performance-based teacher evaluations, the results of which in some cases are linked to new knowledge- and skills-based teacher salary schedules.