“Saturation” is a term that often comes up when we are interested in qualitative methodology and, in particular qualitative interviews. The concept of saturation is related to the number of interviews to be conducted in qualitative research. This article defines the concept of saturation in qualitative research, illustrates it with an example, and gives practical advice. Summary Definition Measuring saturation Advice Sources Definition of the concept of saturation As noted by Marshall et al. (2013) and Guest et al. (2006), the concept of saturation in qualitative research is often invoked...