Validity and Validation in Language Testing: Current State and Future Guidelines in Aphasiology

Assessment of language for individuals suffering from stroke or other brain injury is imperative for diagnosis and management. Comprehensive standardized aphasia tests have been used for decades, and it is important to ensure that these tests possess the quality that supports their use as clinical tools. Test validity is a key consideration in this regard. This paper provides a historical account of the evolution of the concept of test validity. A review of the state of current practices in the field of aphasia testing is provided using a critical analysis of the validation efforts of three major aphasia tools. One kind of validity evidence, consequences of test use, is given special consideration to identify its role in aphasia testing in comparison to the education and psychological measurement literature. Suggestions and practical guidelines for professionals in the field of language disorders will be offered to assist in building validation plans for current and prospective test designers.