As required by the No Child Left Behind Act of 2001 (NCLB), most school districts with low-performing schools offer public school choice and supplemental educational services. However, researchers found that, although the total number of students participating in both options has increased substantially since NCLB began, only a small proportion of eligible students actually participated in the NCLB educational options, for a variety of reasons. (Contains 1 footnote.) [This research brief describes work done for the U.S. Department of Education and documented in "State and Local Implementation of the No Child Left Behind Act: Volume VII--Title I School Choice and Supplemental Educational Services: Final Report," by Georges Vernez, Scott Naftel, Karen Ross, Kerstin Carlson Le Floch, Christopher Beighley, Brian Gill, Beatrice Birman, Michael Garet, and Jennifer O'Day.]