The internal validity of observational study is often subject to debate. In this study, we define the counterfactuals as the unobserved sample and intend to quantify its relationship with the null hypothesis statistical testing (NHST). We propose the probability of a robust inference for internal validity, that is, the PIV, as a robustness index…

Working memory capacities are associated with mathematical development. Many studies have tried to improve working memory abilities through training. Furthermore, the central executive has been shown to be the component of working memory, which is the most strongly related to numerical and arithmetical skills. Therefore, we developed a training…

In this study, we explored the influence of kindergarten children's perspectives of school on their literacy and self-regulation outcomes. Children's early perspectives were captured in a three-question, finger-puppet interview. Responses to the interview questions were coded thematically as being academic and/or social in nature, and were…

When a child does not seem to be ready for primary school, a popular practice is to grant the child more time by letting it repeat kindergarten. However, previous quasi-experimental research demonstrated negative, though diminishing, effects of kindergarten retention on academic learning during the first years of primary school. The present study…

Kindergarten retention is a popular practice for children who are considered unready for primary school. However, past research has not yet succeeded to find consistent, strong empirical evidence supporting the practice. In the current study, kindergarten repeaters' development in nine psychosocial domains is compared with that of equally at risk…

Preschoolers' experiences with shapes are important because geometry is foundational to aspects of mathematics and it is now part of the Common Core for school-readiness. Exposure to shapes also provides experiences that are key to developing spatial thinking more broadly. Yet achieving a strong conceptual understanding of geometric categories can…

Research Findings: This study used data from a national sample to examine differences in school outcomes at the end of kindergarten between Head Start children who attended full-day and half-day programs. Propensity scores were used to match children who experienced different intensities of the program on a series of demographic characteristics in…

Propensity score analysis (PSA) has been used in a variety of settings, such as education, epidemiology, and sociology. Most typically, propensity score analysis has been implemented within the conventional frequentist perspective of statistics. This perspective, as is well known, does not account for uncertainty in either the parameters of the…

The authors examined long-term outcomes for children who experienced delayed entry to kindergarten or kindergarten retention. They used a cohort of 6,841 students to compare these groups to each other and typically progressing peers. First, the authors compared the groups on demographic and early childhood variables. For the long-term school-based…

As policymakers contemplate expanding preschool opportunities for low-income children, one possibility is to fund 2, rather than 1 year of Head Start for children at ages 3 and 4. Another option is to offer 1 year of Head Start followed by 1 year of pre-K. We ask which of these options is more effective. We use data from the Oklahoma pre-K study…

As policy-makers contemplate expanding preschool opportunities for low-income children, one possibility is to fund two, rather than one year of Head Start for children at ages 3 and 4. Another option is to offer one year of Head Start followed by one year of pre-k. We ask which of these options is more effective. We use data from the Oklahoma…

This article reports the findings from a comparative analysis that examined several mathematical content strands, reasoning processes, and emphasis on technology in prior K-8 state mathematics standards and the Common Core State Standards for Mathematics (CCSSM). Various methodological tools were utilized to compare and contrast CCSSM with prior…

Purpose: The authors examined initial acquisition of mental graphemic representations (MGRs) for a set of pseudowords in children with language impairment (LI). They also determined whether the linguistic properties of the words (i.e., phonotactic and orthotactic probabilities) influenced MGR learning and whether the ability to acquire initial…

In this study we test the performance of some nonexperimental estimators of impacts applied to an educational intervention--reduction in class size--where achievement test scores were the outcome. We compare the nonexperimental estimates of the impacts to "true impact" estimates provided by a random-assignment design used to assess the…