Table 2.

Quality assessment using Downs and Black score for reviewers 1 (R1) and 2 (R2). Total quality score ≥ 20 = good, 15–19 = fair, ≤ 14 = poor.

Author, year	Reporting R1	Reporting R2	External validity R1	External validity R2	Internal validity-bias R1	Internal validity-bias R2	Internal validity-confounding R1	Internal validity-confounding R2	Power R1	Power R2	R1 total quality score	R2 total quality score	Overall consensus on quality
Bezalel et al., 2010 [27]	8	10	1	1	3	5	2	4	1	1	15	19	Fair
Brosseau et al., 2012 part 1 [18]	10	9	1	1	7	7	5	3	0	0	23	21	Good
Brosseau et al., 2012 part 2 [19]	11	9	2	1	5	7	5	3	0	0	23	20	Good
Coleman et al., 2012 [20]	10	10	1	1	6	6	5	5	1	1	23	23	Good
Ettinger et al., 2006 [28]	12	10	2	2	3	6	5	4	1	1	23	23	Good
Farr et al., 2010 [29]	9	10	3	2	3	5	5	5	0	0	20	22	Good
Hurley et al., 2007 [15]	9	11	1	2	7	6	4	5	1	1	22	25	Good
Hurley et al., 2012 [30]	10	10	1	2	5	5	5	5	1	1	22	23	Good
Jessep et al., 2009 [21]	8	8	2	1	4	6	5	4	0	0	19	19	Fair
Kovar et al., 1992 [31]	11	11	2	3	4	5	3	4	0	0	20	23	Good
Sullivan et al., 1998 [16]	10	9	2	3	6	6	3	3	0	0	21	21	Good
Mazzuca et al., 1997 [32]	10	12	1	2	5	6	4	4	0	0	20	24	Good
McKnight et al., 2010 [33]	11	10	1	2	5	5	5	4	1	1	23	22	Good
Nunez et al., 2006 [34]	10	9	2	2	5	4	3	4	1	1	21	20	Good
Ravaud et al., 2009 [22]	10	11	1	3	6	7	6	3	0	1	23	25	Good
Thomas et al., 2002 [35]	8	10	2	2	6	6	4	3	1	1	21	22	Good
Thomee et al., 2010 [23]	7	7	2	1	3	5	3	3	1	1	16	17	Fair
Victor et al., 2005 [24]	9	10	4	3	5	7	3	4	1	1	22	25	Good
Wetzels et al., 2008 [25]	10	9	3	2	5	6	3	4	1	1	22	22	Good
Yip et al., 2007 [17]	9	9	2	2	4	4	4	4	1	1	20	20	Good
Yip et al., 2008 [36]	8	8	2	1	3	5	4	3	1	1	18	18	Fair