2. Methodological quality.

Study	1	2	3	4	5	6	7	8	9	10	Total
Aigne 2006	1	0	0	1	0	0	0	0	0	1	3
Bonk 2000	1	0	1	1	0	0	0	1	0	1	5
Borchgrevink 1998	1	0	1	1	1	0	0	1	0	1	6
Brison 2006	1	1	1	1	1	0	0	1	1	0	7
Bunketorp 2006	1	1	1	1	1	0	0	1	1	1	8
Crawford 2004	1	0	0	1	0	0	0	0	0	0	2
Ferrari 2005	1	0	1	1	1	1	0	1	0	1	7
Fialka 1989	1	0	0	0	0	0	0	1	1	1	4
Fitz‐Ritson 1995	1	0	0	0	0	0	0	1	1	1	4
Florio 1999	1	0	0	0	0	0	0	0	0	0	1
Foley‐Nolan 1992	1	0	1	1	1	1	1	1	1	1	9
Hendriks 1996	1	0	0	1	0	0	0	0	0	1	3
McKinney 1989	1	0	1	1	1	0	0	0	0	0	4
Mealy 1986	1	0	1	0	1	0	0	1	0	1	5
Oliveira 2006	1	0	1	1	0	0	0	1	0	1	5
Pennie 1990	1	0	0	0	0	0	0	0	0	0	1
Provinciali 1996	1	0	1	1	1	0	0	1	1	1	7
Rosenfeld 2000	1	1	1	1	0	0	0	1	0	0	5
Schnabel 2004	1	1	1	1	0	0	0	1	1	1	7
Scholten‐Peeters 2006	1	1	0	1	1	0	0	1	1	1	7
Söderlund 2000	1	0	1	1	0	0	0	1	0	0	4
Söderlund 2001a	1	0	0	1	1	0	0	1	0	0	4
Thuile 2002	1	0	0	1	0	0	0	1	0	0	3