Internal Reliability

A psychometric property that measures whether all items in a questionnaire or instrument contribute consistently to the overall score. It is commonly assessed using Cronbach's alpha, where values of 0.7 and above are generally considered acceptable. In accessibility research, internal reliability is important when validating translated or adapted versions of standardized instruments to ensure the translation preserves the coherence of the original. For instance, when translating usability scales into sign languages, researchers verify that the translated items still measure the same underlying construct as a unified set.