Reliability is a crucial component of the measurement process. It is used in the theoretical characterization of communication disorders, assessment of individuals with communication disorders, and evaluation of intervention efficacy. Measurement is a process of representing theoretical constructs through observable events scored by an observer. This entry discusses measurements’ internal cohesiveness and repeatability with respect to their uses in assessing individuals and evaluating intervention efficacy.

The theoretical constructs of interest in communication disorders are often cognitive/motoric abilities developed by the person’s nervous system, including understanding of spoken language, construction of language units, speech fluency, and production of speech sounds, to name a few. The largely unobservable internal neural organization of these abilities is represented in the measurement process through an operational definition in which an observable ...