Purpose: Using data from 1,868 children from the US, Australia, and Sweden who took a 10-word spelling test in kindergarten and a standardized spelling test in Grades 1, 2, and (except for the Australian children) Grade 4, we examined two questions. First, does the quality of a child's errors on the kindergarten test help predict later spelling…

Across multiple schools and sites, the impact of grade-at-intervention was evaluated for children at risk or meeting criteria for reading disabilities. A multiple-component reading intervention with demonstrated efficacy was offered to small groups of children in 1st, 2nd, or 3rd grade. In a quasi-experimental design, 172 children received the…

In this study, we examined the relationship of growth trajectories of oral reading fluency, vocabulary, phonological awareness, letter-naming fluency, and nonsense word reading fluency from 1st grade to 3rd grade with reading comprehension in 1st, 2nd, and 3rd grades. Data from 12,536 children who were followed from kindergarten to 3rd grade…

This article analyzes the magnitude of individual differences in academic achievement and their growth over the first 9 years of schooling. The author anchors the widening-gap phenomenon on the theoretical recognition of large individual differences in learning pace, which logically leads over time to an increasing gap in knowledge and skills…

The authors examined developmental and individual differences in pure numerical estimation, the type of estimation that depends solely on knowledge of numbers. Children between kindergarten and 4th grade were asked to solve 4 types of numerical estimation problems: computational, numerosity, measurement, and number line. In Experiment 1,…