Previous literature suggests that academic achievement and self-concept among adolescents in the general education population are positively related (e.g., Huang, 2011). For students with disabilities, however, the correlation between academic achievement and self-concept is sometimes negative and non-significant (Daniel & King, 1995; Feiwell,…

Discusses difficulties encountered in use of the Scheffe procedure to locate the most significant parametric function within a linear statistical model that has been tested and rejected by, for example, analysis of variance. A solution to the problems is presented. (TJH)

In the article the author refutes J. Fletcher and P. Satz's analysis of the etiology of reading disability on logical, theoretical, and empirical grounds. (Author/PHR)

In the rejoinder the authors describe the methodological and interpretive factors in the Vellutino et al, experiments which limited the degree to which the studies refuted perceptual deficit hypotheses of reading disability. Note: for more of the interchange see EC 114 687-688. (Author/PHR)

Two methodological problems often arising in dyslexia research are considered. The first problem concerns the validity of experimental measures and the related problem of interpreting null results. The second problem involves the effects of sampling from a disabled population if the disorder under investigation has multiple unknown origins.…

Because of criticisms leveled at statistical hypothesis testing, some researchers have argued that measures of effect size should replace the significance-testing practice. We contend that although effect-size measures have logical appeal, they are also associated with a number of limitations that may result in problematic interpretations of them…