Table 1.

Included systematic reviews

Reference	Search date	Aim of review	Study design included	Number of included studies	Main conclusion stated by authors	Studies that match our inclusion criteria
Flodgren et al. 2011 [15]	May 2011	Evaluate the effectiveness of external inspection of compliance with standards in improving healthcare organizations behavior, healthcare professionals behavior and patient outcomes	RCT, CCT, ITS, CBA	Two in total, 1 RCT, 1 ITS	No firm conclusion were drawn due to paucity of high-quality controlled evaluations	Salmon et al. [18]
Matrix Knowledge group 2010 [16]	August 2010	Produce a general overview of results obtained and methodologies used to assess impact of accreditation	Studies containing an element of comparison	56 in total, 40 studies with quantitative design of which 1 study presented empirical data	Most studies suggest that accreditation/certification has an impact on the organization or on the professional practice. The impact on health outcomes or improvement in these outcomes was not demonstrated.	Salmon et al. [18]
Alkhenizan & Shaw 2011 [17]	June 2009	Evaluate the impact of accreditation programs on the quality of healthcare services	Clinical trials, observational studies and qualitative studies	26 in total, 10 studied accreditation of hospitals of which 1 had a hospital control group	Accreditation improves the process of care provided by healthcare services	Salmon et al. [18]

A synthesis of the three included systematic reviews