Table 2.

Quality assessment of included reviews using the AMSTAR tool

	Question	Weed et al14	McCartney et al6
1.	Was an ‘a priori’ design provided?	Y	Y
2.	Was there duplicate study selection and data extraction?	Y	Y
3.	Was a comprehensive literature search performed?	Y	Y
4.	Was the status of publication (ie, grey literature) used as an inclusion criterion?	Y	Y
5.	Was a list of studies (included and excluded) provided?	N-only included studies	N-only included studies
6.	Were the characteristics of the included studies provided?	Y	Y
7.	Was the scientific quality of the included studies assessed and documented?	Y	Y
8.	Was the scientific quality of the included studies used appropriately in formulating conclusions?	Y	Y
9.	Were the methods used to combine the findings of studies appropriate?	Y	Y
10.	Was the likelihood of publication bias assessed	Y	N/A—authors state this not possible
11.	Was the conflict of interest stated?	U (although commissioned by Department of Health	Y
	Total	9	9

N, no; N/A, not applicable; U, unclear; Y, yes.