In 2002, President George W. Bush signed the No Child Left Behind Act (NCLB), which added accountability to President Lyndon Johnson's original Title I legislation of 1964. Specifically, it required that all children in Grades 3-8, by school year 2014, regardless of socioeconomic status, perform at or above grade level requirements in mathematics and language arts. Since that time, research has investigated the performance levels of Title I and non-Title I schools in various states; however, there has been no current analysis of those performance levels in Mississippi. The purpose of this study was to measure the difference in achievement of Title I and non-Title I 4th grade students in Mississippi. The Mississippi Curriculum Test 2 (MCT2) was the sole instrument used to measure student achievement to fulfill the requirement of achievement mandated by NCLB. Using a constructivist approach, school data from the 2011 MCT2 test scores from three Central Mississippi school districts (N = 57 schools) were analyzed using inferential and nonparametric tests, specifically t-tests and Mann-Whitney tests. The analysis showed no statistical difference between the scores of Title I and non-Title I schools, a finding that was likely due to the small sample size. These findings guided the creation of a professional development module on differentiated instruction, one that will be implemented by teachers and administrators in several Mississippi school districts. Positive social change is evident from this project by the possible increase in achievement of all students, regardless of socioeconomic status or funding. [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://www.proquest.com/en-US/products/dissertations/individuals.shtml.]