ABSTRACT
This chapter presents the most complete picture to date of skills in dyslexic children. It argues that an important target for dyslexia research is to develop a 'taxonomy' – a principled classification system based not on arbitrary descriptions of dyslexic performance, but on some underlying causal mechanism. The specific issues addressed in the research programme were: first, what proportion of dyslexic children showed each type of deficit; second, whether there is some deficit which is the 'primary' one, which underlies the other deficits; and third, whether it is possible to identify different subtypes of dyslexia, such that each subtype has discriminably different characteristics. There is considerable controversy over methods of defining dyslexia, and in particular whether it is appropriate to differentiate between dyslexic children and slow learners – poor readers whose reading is nonetheless at about the level of the rest of their attainments.
