The No Child Left Behind (NCLB) Act of 2001 has brought about a sea change in education in the United States. While the act has its detractors?as well as its admirers?among educators, parents, government officials, and the media, there is little doubt that NCLB has cast new light on public schools by using hard data to focus on achievement gaps at the individual school level.This topical summary discusses one key aspect of the No Child Left Behind (NCLB) Act of 2001: adequate yearly progress (AYP). It reviews the major requirements of AYP, examines how the five Northwestern states determine AYP, and reports what the current data tell us about the achievement gaps among groups of students in these states. Finally, this report looks at how the top state education officials are viewing AYP results.