Conceptual Knowledge-Based Strategy Training in Single-Digit Calculation: A Single Case Intervention Study in a Child with Specific Language Impairment

The aim of this single-case intervention study was to examine whether a conceptual knowledge-based strategy training would improve the accuracy of single-digit arithmetical calculation in a child with specific language impairment. The intervention concerned an 11-year-old Finnish-speaking child with specific language impairment. He was trained individually once a week for three months. On the basis of his baseline performance single-digit arithmetical problems were divided into "well-known arithmetical problems" and "error-prone arithmetical problems". Error-prone problems were taught in meaningful relation to well-known problems, which he repeatedly solved correctly by using arithmetical fact knowledge. An intervention study design was used consisting of six baseline and three follow-up assessments. The results show that the participant calculated additions, subtractions and multiplications more accurately after the intervention was applied. In subtraction he also used more retrieval-based strategies after than before the intervention. The results suggest that an intervention programme targeted at improving calculation skill based on conceptual knowledge is beneficial, especially when children have weaknesses in use of counting procedures and in direct memory retrieval. (Contains 5 figures and 1 table.)