The MacArthur-Bates Communicative Development Inventories (CDI) are widely used, parent-report instruments of language acquisition. Here, we focus on the word-inventory sections of the instruments, and show two different approaches to modeling CDI data, based on real-world needs. First, we show that Words & Gestures data collected…

Introduction: The objective of this study is to find out if there are differences in selective and sustained attention between children with different subtypes of ADHD and children with learning disorders (LD), in order to improve the differential diagnosis between ADHD and PD and between the different subtypes of ADHD. Method: The sample…

Charles Spearman and L. L. Thurstone were pioneers in the field of intelligence. They not only developed methods to assess and understand intelligence, but also developed theories about its structure and function. Methodologically, their approaches were not that distinct, but their theories of intelligence were philosophically very different --…

We compared the Wechsler scores of individuals with twice-exceptionality (2e) and giftedness using a three-level Bayesian meta-analysis. Ninety-five effect sizes were calculated from 15 studies (n = 2,106). Results show that individuals with 2e who have learning disabilities perform lower than individuals with giftedness in Full-Scale Intelligence…

The structural validity of the "Wechsler Intelligence Scale for Children-Fourth Edition" (WISC-IV) was evaluated using confirmatory factor analysis for a clinical sample of 1,537 students diagnosed with specific learning disabilities (SLD) by school psychologists in two large southwestern school districts. Results indicated that a…

Within the Canadian context, the two major learning disability classification systems are arguably the American Psychiatric Association's (APA) "Diagnostic and Statistical Manual of Mental Disorders" and the Learning Disabilities Association (LDAC) of Canada's "Official Definition of Learning Disabilities." Several of the more…

Students' explanations of their mathematical thinking and conclusions have become a greater part of the assessment landscape in recent years. With a sample of 71 fourth-grade students at risk for mathematics learning disabilities, we investigated the relation between student accuracy in comparing the magnitude of fractions and the quality of…

Working memory (WM) has long been associated with deficiencies in reading. Approximately 35% of students in the United States who receive special education services do so under the category of specific learning disability (SLD). The study's theoretical underpinning was Baddeley's model of WM; previous research revealed a significant literature gap…

Objective: Accurate estimation of developmental trajectories can inform instruction and intervention. We compared the fit of linear, quadratic, and piecewise mixed-effects models of reading development among students with learning disabilities relative to their typically developing peers. Method: We drew an analytic sample of 1,990 students from…

Purpose: To examine if a community sample of 11-year-old children with persistent stuttering have higher anxiety than children who have recovered from stuttering and nonstuttering controls. Method: Participants in a community cohort study were categorized into 3 groups: (a) those with persistent stuttering, (b) those with recovered stuttering, and…

Several studies have explored the relationship between dyslexia and creativity, but results have been rather mixed. This study examines whether Italian dyslexic children are more creative than their peers without a reading impairment. One hundred ninety Italian children aged between 9 and 13 participated in this study, divided into two groups:…

Student explanations of their mathematical thinking and conclusions have become a greater part of the assessment landscape in recent years. With a sample of 71 4th-grade students at-risk for mathematics learning disabilities, we investigated the relation between student accuracy in comparing the magnitude of fractions and the quality of students'…

Specific learning disabilities are one of the most common and debilitating disorders experienced by children and adolescents, and students with specific learning disabilities may be particularly vulnerable to anxiety. The Revised Children's Manifest Anxiety Scale, Second Edition (RCMAS-2) is a newly revised measure of chronic, manifest anxiety…

A relationship between motor and mathematical skills has been shown by previous research. However, the question of whether subtypes can be differentiated within developmental coordination disorder (DCD) and/or mathematical learning disability (MLD) remains unresolved. In a sample of children with and without DCD and/or MLD, a data-driven…

This study investigated the effectiveness of five commonly administered academic testing accommodations on reading and math performance in children with Attention-deficit/Hyperactivity Disorder (ADHD). A total of 96 parents of 3rd-8th grade students with ADHD participated. More than half of the sample also had parent-reported learning difficulties…