This meta-analysis examines the effects of vocabulary interventions on pre-K and kindergarten children's oral language development. The authors quantitatively reviewed 67 studies and 216 effect sizes to better understand the impact of training on word learning. Results indicated an overall effect size of 0.88, demonstrating, on average, a gain of…

Given the size of the investment in professional development for early childhood educators and the dependence of educational reform on providing high quality professional development, the knowledge base of effective practices needs to be strengthened. In this paper, the authors report on the results of an effort to better understand the…

The purpose of this design experiment was to research, test, and iteratively derive principles of word learning and word organization that could help to theoretically advance our understanding of vocabulary development for low-income preschoolers. Six Head Start teachers in morning and afternoon programs and their children (N = 89) were selected…

This study examines the effectiveness of scaling up a vocabulary intervention, pre-K-first grade, using a structured adaptation of the World of Words that allowed teachers some autonomy over its implementation. The purpose was to determine whether such an adaptation could maintain fidelity and promote positive child outcomes. Classrooms (pre-K…

The purpose of this study was to support teachers' child-directed language and student outcomes by enhancing the educative features of an intervention targeted to vocabulary, conceptual development and comprehension. Using a set of design heuristics (Davis & Krajcik, 2005), our goal was to support teachers' professional development within the…

The purpose of this study was to examine the hypothesis that helping preschoolers learn words through categorization may enhance their ability to retain words and their conceptual properties, acting as a bootstrap for self-learning. We examined this hypothesis by investigating the effects of the World of Words instructional program, a supplemental…

This meta-analysis is designed to build on the existing knowledge base by examining vocabulary interventions specifically for factors associated with child outcomes for at-risk children. Specifically, the authors addressed the following questions: (1) To what extent are vocabulary interventions an effective method for at-risk children prior to…