“…Administration modes ranged from self completion on site [42,44,47,51], provider/researcher administered either on site (face to face interviews) [28,32], or via telephone [40,41,46], or mailed [30,34,39,43,45,[47][48][49][50]. One innovative study reported the use of trained volunteer patients as 'mystery shoppers' to assess and report their satisfaction with services provided by different health care professionals [36].…”