In this article, we discuss the approach adopted within the Vanderbilt University Learning Disabilities Innovation Hub, which focuses on students with higher-order comorbidity: students with concurrent difficulty with reading comprehension and word-problem solving. The aim of the Hub's Research Project is to test what we refer to as the…

Three cohorts of third-grade students (N = 813) were evaluated on achievement, cognitive abilities, and behavioral attention according to contrasting research traditions in defining math learning disability (LD) status: low achievement versus extremely low achievement and IQ-achievement discrepant versus strictly low-achieving LD. We use methods…

This study examined whether and, if so, how word-problem features differentially affect problem difficulty as a function of mathematics difficulty (MD) status: no MD (n = 109), MD only (n = 109), or MD in combination with reading difficulties (MDRD; n = 109). The problem features were problem type (total, difference, or change) and position of…

This study assessed responsiveness to a 16-week mathematical problem-solving treatment as a function of students' risk for disability. Among 301 third graders, "TerraNova" scores were used to categorize students as at risk for both reading and mathematics disability (MDR/RDR; 20 control and 12 experimental), at risk for mathematics…

This article first describes two types of assessment (problem solving and standard treatment protocol) within a "responsiveness-to-instruction" framework to identify learning disabilities. It then specifies two necessary components (measures and classification criteria) to assess responsiveness-to-instruction, and present pertinent findings from…

This article describes the two basic versions of the responsiveness-to-intervention (RTI) approach for identifying learning disabilities, the problem solving model and the standard-protocol approach. It reviews evidence on effectiveness and feasibility and concludes that more needs to be understood before RTI may be viewed as a valid…

On December 3, 2004, President Bush signed into law the Individuals with Disabilities Education Improvement Act (IDEA, 2004). The revised law is different from the previous version in at least one important respect. Whereas practitioners were previously encouraged to use IQ-achievement discrepancy to identify children with learning disabilities…

A study investigated the mathematical problem-solving abilities of 18 fourth-graders with mathematics disabilities (MD) with and without comorbid reading disabilities (RD). Results demonstrated large deficits for both groups. However, the differences between students with and without RD were mediated by the level of problem solving and by…

A small-group mathematical problem-solving tutorial treatment with explicit instruction including transfer to novel problems was evaluated with 40 students. On word problems and transfer word problems, tutoring effected reliably stronger growth, although effects on real-world problem solving, while moderate to large, were not statistically…