Table 3:

Year published and quality assessment of selected studies

Reference number	Year a	External validity									Internal validity				Informativity					Disagreement b
		a	b	c	d	e	f	sum	g	h	i	j	k	l	sum	m	n	o	sum
12	2000	+	+	-	-	-	-	2	+	-	+	-	-	-	2	+	-	-	1
13	2000	+	+	+	+	+	+	6	+	+	+	+	+	-	5	+	+	+	3
14	2002	+	+	+	-	-	-	3	+	+	+	+	+	-	5	+	+	+	3	l
15	2003	+	+	+	+	-	-	4	+	+	+	+	+	-	5	+	+	+	3
16	2003	+	+	+	+	-	-	4	+	+	+	+	+	-	5	+	+	+	3	M, n, o
17	2003	+	+	+	+	-	-	4	+	+	+	+	+	+	6	+	+	+	3
18	2003	+	+	+	+	+	+	6	+	+	+	+	+	-	5	+	-	+	2
19	2005	+	+	+	+	+		5	+	+	+	+	+	+	5	+	-	-	1
20	2005	+	+	+	+	+	+	6	+	+	+	-	-	-	3	+	+	+	3	J, k, l
21	2005	+	+	+	+	+	+	6	+	+	+	+	+	+	6	+	+	+	3
22	2007	+	+	+	+	+	+	6	+	+	+	+	+	+	6	+	+	+	3
23	2007	+	+	+	+	+	+	6	+	+	+	-	-	-	6	+	+	+	3
24	2008	+	+	+	+	+	+	6	+	+	+	-	-	-	3	+	+	+	3	K, l
25	2008	+	+	+	+	+	-	5	+	+	+	+	-	-	4	+	+	+	3
26	2009	+	+	+	+	+	+	6	+	+	+	+	-	-	4	+	+	+	3
27	2011	+	+	+	+	+	+	6	+	+	+	+	-	-	4	+	+	+	3
28	2012	+	+	+	+	+	+	6	+	+	+	+	+	+	6	+	+	+	3
29	2013	+	+	+	+	+	+	6	+	+	+	+	+	+	6	+	+	+	3
30	2013	+	+	+	+	+	-	5	+	+	+	+	-	-	4	+	+	+	3
31	2015	+	+	+	+	+	-	5	+	+	+	+	-	-	4	+	+	+	3
32	2015	+	+	+	+	+	-	5	+	+	+	+	-	-	4	+	+	+	3
33	2016	+	+	+	+	+	-	5	+	+	+	+	-	-	4	+	+	+	3
34	2016	+	+	+	+	+	-	5	+	+	+	+	+	+	6	+	+	+	3
35	2016	+	+	+	+	+	-	5	+	+	+	+	-	-	4	+	+	+	3
36	2017	+	+	+	+	+	+	6	+	+	+	+	-	-	4	+	-	-	1
37	2018	+	+	+	+	+	+	6	+	+	+	+	-	-	4	+	-	-	1

Items a–o refer to Table 1.

^aYear published.

^bItems on which the two reviewers disagreed