The relevance of Vygotsky's theory of the "zone of proximal development' to the assessment of children with intellectual disabilities.

This paper reports a study which investigated the relevance of Vygotsky's concept of the "zone of proximal development' (ZPD) to the assessment of children with intellectual disabilities. The ZPD is the difference between a child's actual level of development shown by unassisted performance, and his or her potential level as indicated by assisted performance. This study aimed to test the validity of measuring the ZPD both among children with intellectual disabilities and in the area of map use. The results are discussed in terms of their bearing on the issues of assessment, instruction and the concept of intellectual disability.