Over several years, Clark Pleasant Community School Corporation (CPCSC) schools have dedicated significant professional development hours and time to develop Essential Learnings (ELs) along with proficiency scales that could guide the content of classroom assessments used to determine student mastery. This executive summary highlights key findings from statistical analyses of the relationship between EL mastery as indicated by proficiency scales and 2015 proficiency rates for CPCSC students on the Indiana Statewide Testing for Educational Progress (ISTEP) English language arts (ELA) and mathematics assessments in grades 3 and 4. [This report was prepared for the Clark Pleasant Community School Corporation. For "An Analysis of the Relationship Between Essential Learning Mastery and Mathematics Achievement in Grades 3 and 4"," see ED574871.]