Saturation in Qualitative Health Research: An Overview and Analysis Through the Lens of Epistemic Injustice

The concept of saturation was originally developed within grounded theory. It has since been extended and widely adopted as a marker of rigor throughout qualitative health research. Although saturation can prove useful, there are growing concerns regarding its uncritical adoption as a universal standard of high-quality analysis. While this critique is not new, we ground our argument within the concept of epistemic injustice, to contend that the inappropriate use of saturation risks enacting epistemic injustice by marginalizing certain forms of data and certain methodologies. This, in turn, limits what can be known about health and illness, with the potential to cause material harm and produce and sustain health inequities. First, we introduce the concept of epistemic injustice, following which we provide an overview of saturation to describe the different models, discuss their contingent nature, and call attention to the underlying positivist logic embedded in saturation. Next, we analyze the exclusionary effects of saturation in qualitative health research through the lens of epistemic injustice. We conclude with recommendations for a more context-sensitive and reflexive engagement with saturation, and a shift away from procedural adherence to checklist-based standards that enforce its use in academic knowledge production.