In the 2014 report, "Closing the Achievement Gap Through Modification of Neurocognitive and Neuroendocrine Function: Results from a Cluster Randomized Controlled Trial of an Innovative Approach to the Education of Children in Kindergarten," researchers examined the impacts of "Tools of the Mind" on cognitive and academic outcomes for 759 kindergarteners from 29 schools. "Tools of the Mind" promotes self-regulated learning and involves teacher-led interactions between classmates, individualized instruction, and dramatic play. Students joined the study after random assignment and study authors did not show that the analytic groups of students were similar at the start of the study. Therefore, the study does not meet WWC group design standards. A glossary of terms is included. [The following study is the focus of this "Single Study Review": Blair, C., & Raver, C. C. (2014). Closing the achievement gap through modification of neurocognitive and neuroendocrine function: Results from a cluster randomized controlled trial of an innovative approach to the education of children in kindergarten. "PloS ONE," 9(11), e112393.]