Review data informed development of the key informant interview
schedule and complemented evidence from interviews. Qualitative
research does not have consistent standards for sample size
(e.g. Morse, 1995; Patton, 2002) and recommendations vary widely
(e.g. Back, 2012; Brannen, 2012; Miller, 2012). The theoretical endpoint
of data collection and analysis and a gauge of internal study
validity is data saturation, described by Morse (1995, p. 147–148)
as ‘‘‘data adequacy’ operationalized as collecting data until no new