Moving beyond "until saturation was reached": Critically examining how saturation is used and reported in qualitative research.

Saturation is well known in qualitative research as a key methodological concept and criterion for discontinuing data collection and/or analysis. Often, it is used by qualitative researchers in making decisions related to the adequacy of their sample size (1). It is becoming increasingly common for decisions to take place at the planning stage in order to propose sample size to potential funders or ethical review boards.