The purpose of this study was to provide a greater understanding of the broader characteristics of the lowest performing elementary and middle schools in Illinois, as little analysis of this data had been conducted. Furthermore, little to no research has explored the vertical and horizontal alignment of math curricula and its correlation to achievement scores. The results of the study suggest that the impact of COVID-19 has taken a toll on our K-12 students and teachers, as well as leaders. There is a higher percentage of principal turnover in the last six years, in schools summatively designated comprehensive, that have students of color, low-income students, and English Learners. Another key finding from this research shows that effective strategies are needed to support school improvement in schools with a high percentage of students of color and low income. To positively impact school improvement practices in the lowest performing schools, having ongoing conversations about best practices in school improvement in our schools, will help develop the foundation for building the capacity of school leaders to implement and sustain effective school improvement practices. [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.]