The main focus of this paper is to discuss the importance of “evaluating the process of change” (i.e., process evaluation) in people with disability by studying their lived experiences. Detailed discussion is made about “why and how to investigate the process of change in people with disability?” and some specific examples are provided from studies on patient journey of persons with hearing impairment (PHI) and their communication partners (CPs). In addition, methodological aspects in process evaluation are discussed in relation to various metatheoretical perspectives. The discussion has been supplemented with relevant literature. The healthcare practice and disability research in general are dominated by the use of outcome measures. Even though the values of outcome measures are not questioned, there seems to be a little focus on understanding the process of change over time in relation to health and disability. We suggest that the process evaluation has an additional temporal dimension and has applications in both clinical practice and research in relation to health and disability.