NCLB requires annual testing of at least 95% of all students to measure progress in reading and math, and requires schools and school divisions to meet targets for achievement in four subgroups:
NCLB sets annual objectives (or targets) for student participation and performance on these reading and math tests. As we move closer to 2014 - the 100%-proficiency deadline - the AYP bar will be raised each school year. For a school or school division to "make AYP" it must meet or exceed all targets for participation in statewide testing, achievement in reading and math, and attendance (elementary and middle schools) or graduation (high schools). Missing a single target results in a school or school division not making AYP.
NCLB information is available on the U.S. Department of Education web site.