Abstract

The concept of vulnerability has been hotly debated in research ethics literature. Some critics considered it a useless concept. In 2009—against some of those criticisms—I defended the importance of understanding this concept in terms of layers instead of applying it as a label given to certain subpopulations. In this paper, I present some of the limits of this analysis and I also explore the similarities and differences this approach has when compared to using a taxonomy as another answer on how to assess vulnerability. I present the notion of cascade vulnerability and underscore the dispositional character of layers and their relevance to identify and evaluate layers of vulnerability. Finally, I show how this layered account has been incorporated in important documents such as the new 2016 CIOMS-WHO Guidelines.