“…Despite its hidden nature, the presence of informal payments can impose threats to the health care sector per se . They can impede efficiency and affect quality of care, jeopardize equality and equity in access to health care services, impose ‘cream-skimming’, affect the solidarity principle of insurance-based health care systems, and even threaten democratic and inclusion values (Thompson and Witter, 2000; Balabanova and McKee, 2002; Ensor, 2004; Allin et al ., 2006; Gaal et al ., 2006a; Vian and Burak, 2006; Lewis, 2007; Cohen, 2011; Mæstad and Mwisongo, 2011). Therefore, informal payments are an important health policy issue.…”