The Kindergarten Early Development Instrument Predicts Third Grade Academic Proficiency

School readiness skills predict later educational achievement, health, and social-emotional outcomes. Measures of school readiness can provide valuable information to assess both the impact of strategies and policies that prepare children for school as well as informing strategies for improving children's educational trajectories across their school years. The Early Development Instrument (EDI) is a measure of school readiness skills based on teacher-reported observational recall. It has been used extensively in Canada and Australia and is in the early stages of adoption in a number of U.S. cities. The current study uses data from roughly 3,000 children followed longitudinally from kindergarten through third grade from 7 school districts in Orange County, California. The study assesses whether EDI ratings in kindergarten predict third grade proficiency in mathematics and English Language Arts on state assessments. Ratings on the EDI were strongly associated with proficiency in both academic areas, even in the presence of controls for child-level factors and neighborhood fixed effects. Among its components, ratings on the language and cognitive development, communication skills and general knowledge, and social competence domains strongly differentiated children's likelihood of later proficiency in both academic areas. Implications for improving comprehensive early childhood education and schooling policies based on indicators of school readiness are discussed.