The 2001 reauthorization of the Elementary and Secondary Education Act (ESEA), also known as the No Child Left Behind (NCLB) legislation, has been called the most far-reaching federal education bill in nearly four decades. The law's comprehensive assessment provisions address areas from school choice to low-performing schools and increased accountability. School testing, however, is the area that has drawn the most scrutiny from the states. The authors examine reactions to the assessment features of the legislation, considering what both proponents and critics of the legislation say about federally-mandated educational assessment. The document's authors then link comprehensive assessment with school improvement and productive school management.