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…

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…

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…

The purpose of this study was to determine whether students retained in first grade, relative to similarly low-achieving students who were promoted, differed in the number of remedial educational services received by students in the pre-retention year and in the repeat year. Study participants were 769 relatively low-achieving first-grade…