Conceptual Models of Disability: The Development of the Consideration of Non-Biomedical Aspects

In 1965, Saad Z. Nagi published a very influential conceptual model of disablement in which he distinguished among several aspects of the disability phenomenon. In the following decades, several other conceptual models were proposed, increasingly taking up ideas and demands emerging from the disability movement, especially the social model of disability. In this review, three generations of these conceptual models of disability are presented, contrasted, and evaluated, especially in regard to the thematization of non-biomedical aspects. The elaboration ensues with the help of the criterion of construct clarity and thus focuses on the model’s definitions of components, application context, value assumptions, and content validity. For the latter aspects, the health sociological triad of disease/illness/sickness is employed. These concepts are adapted to the disability phenomenon. While the first generation focuses on a mainly biomedical disablement process, only later supplemented with other context factors, the second generation attempts to combine this assortment with a relational understanding of disability and also increasingly departs from conceptualizing the components negatively. Finally, the third generation of conceptual models is more holistic, and gives more weight to environmental aspects, but still somewhat neglects the individual aspects.