Children with better academic and behavioral functioning when they start kindergarten often have better educational and societal opportunities as they grow up. For instance, children entering kindergarten with higher reading and math achievements are more likely to go to college, own homes, be married and live in higher-income neighborhoods as adults. A new study points to the very early roots of differences in school readiness, with vocabulary growth playing a particularly important role. Researchers found that children with larger oral vocabularies by age 2 arrived at kindergarten better prepared academically and behaviorally than their peers. This information can help target early intervention efforts. The study was co-authored by UCI education professor George Farkas and Paul Morgan, associate professor of education at Pennsylvania State University. Researchers analyzed nationally representative data for 8,650 children in the Early Childhood Longitudinal Study-Birth Cohort. The study appears in the journal Child Development.