Content validity in the development and adaptation processes of measurement instruments

This study sought to conduct a review of content validity, which is an important phase of processes of construction and adaptation of measurement instruments. Research of comprehensive literature was conducted by means of a review of national and international databases. Initially, a description of the conceptual basis and the measurement methods used in content validity was made, with emphasis on its application in the healthcare area. It was seen that controversy exists in the literature on the terminology and concept of content validity. The recommended procedures used to check content validity during the construction and adaptation processes of instruments were described, especially the judges' assessment, which can involve qualitative and quantitative procedures. The number, selection and qualification of these judges were also described. The different methods used to quantify the level of agreement among the experts were verified, mainly the Content Validity Index (CVI). This study described aspects of the content validity process, one of the procedures to be considered by healthcare researchers and professionals who are interested in using reliable and appropriate measurements and instruments scales for given population groups.