Enriching the concept of vulnerability in research ethics: An integrative and functional account.

The concept of vulnerability is widely used in research ethics to signal attention to participants who require special protections in research. However, this concept is vague and under-theorized. There is also growing concern that the dominant categorical approach to vulnerability (as exemplified by research ethics regulations and guidelines delineating vulnerable groups) is ethically problematic because of its assumptions about groups of people and is, in fact, not very guiding. An agreed-upon strategy is to move from categorical towards analytical approaches (focused on analyzing types and sources of vulnerability) to vulnerability. Beyond this agreement, however, scholars have been advancing competing accounts of vulnerability without consensus about its appropriate operationalization in research ethics. Based on previous debates, we propose that a comprehensive account of vulnerability for research ethics must include four components: definition, normative justifications, application, and implications. Concluding that no existing accounts integrate these components in a functional (i.e., practically applicable) manner, we propose an integrative and functional account of vulnerability inspired by pragmatist theory and enriched by bioethics literature. Using an example of research on deep brain stimulation for treatment-resistant depression, we illustrate how the integrative-functional account can guide the analysis of vulnerability in research within a pragmatist, evidence-based approach to research ethics. While ultimately there are concerns to be addressed in existing research ethics guidelines on vulnerability, the integrative-functional account can serve as an analytic tool to help researchers, research ethics boards, and other relevant actors fill in the gaps in the current landscape of research ethics governance.