Dyslexia is a term widely used to describe reading characterised by problems with the fluent and accurate letter or word recognition. Nevertheless, there is no consensus about the definition, origin, and diagnosis of dyslexia and the term is often used very differently by researchers and practitioners. In many cases, research findings are employed…

Most study samples show less variability in key variables than do their source populations due most often to indirect selection into study participation associated with a wide range of personal and circumstantial characteristics. Formulas exist to correct the distortions of population-level correlations created. Formula accuracy has been tested…