Following a high-quality early care and pre-K experience, the kindergarten-through-third-grade years set the foundation upon which future learning builds; and strengthening this continuum creates opportunities for later success. Key components of a quality experience in K-3 include school readiness and transitions, kindergarten requirements, educator quality, prevention, intervention and assessments, and social and emotional learning and mental health. Education Commission of the States researched the policies and regulations that guide these key components in all 50 states to provide this resource and many others. The data in this document show that at least 17 states and the District of Columbia require retention with good cause exemptions. Good cause exemptions outlined in state policy range from exemptions for students who are English language learners to students who demonstrate reading proficiency through alternative assessments and evaluations.