The "No Child Left Behind" (NCLB) Act of 2001, Public Law 107-110 (U.S. Congress), was passed by Congress in response to perceived failure of the public school system to effectively educate students, particularly disadvantaged students in the United States. The relationship of NCLB school choice to student achievement has not been clearly established. This causal-comparative study examined the following: (a) FCAT mathematics and reading achievement gains of targeted fourth through eighth grade NCLB choice students and a comparison group of eligible non-choosers with matching demographic characteristics; (b) the pre-test academic ability levels of NCLB choice students in fourth grade through eighth grade as compared with the achievement levels of eligible non-choosers, and (c) differences in the ethnic and socioeconomic characteristics of choice students versus eligible non-choosers in kindergarten through eighth grade, and the impact of those differences on the demographic composition of individual schools. Differences in the achievement gains and in the pre-test achievement levels of NCLB choice students and the comparison groups were not statistically significant. NCLB choice students tended to have different ethnic and socioeconomic characteristics from their non-choosing peers. The effect of NCLB choice on Title I students and schools was discussed, and NCLB choice implementation issues were identified. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]