Language matches: Illuminating or confounding?

The practice of matching younger, language-matched controls, in addition to age-matched controls, is often used in studies of language-disordered children to examine the role of 'language level' on performance. However, the interpretation of the relative performance of subjects in studies using such dual control groups is problematic. Conceptual concerns arise with the use of language matches because language is a multidimensional skill that is not reflected equivalently for the language-disordered children and their language-matched controls. Furthermore, matching by language level inevitably introduces an extraneous age effect that confounds interpretation. In addition, erroneous interpretations of null findings can occur when no differences are found between language-disordered and language-matched groups.