Despite evidence provided through decades of educational research regarding effective practices in high-performing, high-poverty schools, Mississippi continues to trail other states in improving student achievement outcomes (Annie E. Casey Foundation, 2016). Educational research provides evidence regarding the importance of school leadership, the specific practices school leaders engage in to bring about sustainable improvement, and school leadership preparation and support to improve struggling schools (Elmore et al., 2014; Manna, 2015; Fullan et al., 2006; The Wallace Foundation, 2010). Research also acknowledges leadership to improve failing schools adds complexity and requires a particular set of leadership knowledge and behaviors (Elmore, 2008b; Marzano et al., 2005; Muhammad, 2009; Reeves, 2009). In order to consider solutions to high-poverty struggling school concerns in Mississippi, the quantitative research study was designed to compare the capacity for improvement in high-needs improving and high-needs struggling Mississippi schools. Net gain or loss of Quality of Distribution Index (QDI) scores and School Performance Level (SPL) points over five years of school performance data determined schools' research designations of improving or struggling. Matched school pairs included one improving and one struggling school matched on baseline QDI score, size of school, and school poverty level. A total of 19 schools participated in the research study--12 improving and seven struggling. Of the 19 schools, 14 were matched with a comparable school for a total of seven for matched-pairs testing. The focus of the research was measurement and comparison of internal coherence (IC) defined as "...a school's capacity to engage in deliberate improvements in instructional practice and student learning across classrooms, over time..." (Elmore, Forman, Stosich, & Bocala, 2014). Participating staff and principals completed the Internal Coherence Survey (Elmore & Forman, 2012). Resulting scores were tested in ten hypotheses using paired- and independent-samples "t"-tests, Pearson's correlations, and Kendall's tau-b. The primary hypothesis considered the difference in IC in high-needs improving and struggling schools. A paired-samples "t"-test indicated a statistically significant difference in the capacity for improvement in the two school types. Statistical testing for eight supporting hypotheses confirmed, either through statistically significant results or non-statistically significant results, the viability of internal coherence is a factor to consider in additional research and as a focus for an improvement strategy for high-poverty schools in Mississippi. [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.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]