Missouri longitudinal study of mathematical development and disability

Background. Of all the students, 7 % will experience a severe learning deficit in mathematics before completing high school. These students with a mathematical learning disability (MLD) are joined by another 5–10 % of students with less severe learning difficulties. Aims. The goal is to identify the core deficits that define MLD and mathematical difficulties; identify the cognitive systems that underlie these deficits; and, to develop measures to identify at-risk children. Method. The Missouri project is a prospective kindergarten to 9th grade study of more than 200 students ’ mathematical growth and learning. Students are administered standardized achievement tests and mathematical cognition tasks once a year. A comprehensive working memory battery was administered in 1st and 5th grade, and classroom attention assessed in 2nd to 4th grade. Results. Initial results indicate that children with MLD perform about 1 SD below average on working memory measures, even when IQ is controlled, and perform below average on mathematical cognition tasks that involve number processing an