“…When operational definitions are inconsistent, validity and reliability cannot be documented. Different approaches include the measurement of nonadherence according to demographic characteristics (Bame et al, 1993; Kaplan, DeNour, & Czaczkes, 1974; Leggat et al, 1998), psychological and behavioral variables (Kimmel et al, 1995; Kimmel et al, 1998; O'Brain, 1990), lab values (Arici et al, 1999; Block, Hulbert‐Shearon, Levin, & Port, 1998; Mai, Busby, & Bell, 1999), and comorbid conditions (Kaveh & Kimmel, 2001; Leggat et al, 1998). Demographic characteristics associated with nonadherence include racial group differences (Bame et al, 1993).…”