This study aimed to describe 1-year changes in students' vocabulary in written narratives. Secondary aims included examination of accuracy and the relationship between lexical diversity and achievement. Participants included 749 students in first through eighth grades. Within-subjects 1-year change in diversity, productivity, and accuracy was…

This study explores the co-development of two related but separate reading skills, reading fluency and reading comprehension, across Grades 1-4. A bivariate biometric dual change score model was applied to longitudinal data collected from 1,784 twin pairs between the ages of 6 and 10 years. Grade 1 skills were influenced by highly overlapping…

The present study employed data simulation techniques to investigate the 1-year stability of alternative classification schemes for identifying children with reading disabilities. Classification schemes investigated include low performance, unexpected low performance, dual-discrepancy, and a rudimentary form of constellation model of reading…

The present study seeks to evaluate a hybrid model of identification that incorporates response to instruction and intervention (RTI) as one of the key symptoms of reading disability. The 1-year stability of alternative operational definitions of reading disability was examined in a large-scale sample of students who were followed longitudinally…

Research on the development of reading skills through the primary school years has pointed to the importance of individual differences in initial ability as well as the growth of those skills. Additionally, it has been theorized that reading skills develop incrementally. The present study examined the genetic and environmental influences on 2…

The purpose of this study was to use a mixed methods approach to learn about inadequate response to a year-long multi-tier response to intervention (RTI) model that allowed first-grade students to move up and down tiers. Participants were 156 students who received supplemental intervention services during a larger multi-tier RTI study involving…

This research investigated the immediate and long-term effects of a Tier 2 intervention for beginning readers identified as having a high probability of reading failure using a randomized control trial. First-grade participants (n = 123) were randomly assigned either to a 25-session intervention targeting key reading components, including…

Rates of agreement among alternative definitions of reading disability and their 1- and 2-year stabilities were examined using a new measure of agreement, the affected-status agreement statistic. Participants were 288,114 first through third grade students. Reading measures were "Dynamic Indicators of Basic Early Literacy Skills" Oral…

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…