Country	Number of studies	Study name
Austria	1	Faggiano 2008
Australia	1	Buller 2008 (Australia)
Belgium	1	Faggiano 2008
Canada	3	Armstrong 1990 (Peer); Armstrong 1990 (Teacher); Brown 2002; Denson 1981
China	2	Chou 2006; Wen 2010
Czech Republic	1	Gabrhelik 2012
Denmark	1	De Vries 2003 (Denmark)
Finland	1	De Vries 2003 (Finland)
Germany	4	Faggiano 2008; Hort 1995; Schulze 2006; Weichold 2011 (Peer); Weichold 2012 (Teacher)
Greece	1	Faggiano 2008
Italy	3	Faggiano 2008; Figa‐Talamanca 1989 (F); Figa‐Talamanca 1989 (N.F); La Torre 2010 (A); La Torre 2010 (C)
Netherlands	4	Ausems 2004 (Combined); Ausems 2004 (In school); Ausems 2004 (Out School); Crone 2011; De Vries 1994 (High); De Vries 1994 (Voc); Van Lier 2009
Portugal	1	De Vries 2003 (Portugal)
Spain	2	Faggiano 2008; Garcia 2005
South Africa	1	Resnicow 2008 (Harm Min); Resnicow 2008 (LST)
Sweden	1	Faggiano 2008
Thailand	1	Seal 2006
UK	4	Aveyard 1999; Conner 2010 (I); Conner 2010 (SE); De Vries 2003 (UK); Nutbeam 1993 (FSE); Nutbeam 1993 (FSE+SAM); Nutbeam 1993 (SAM)
USA	27	Ary 1990; Botvin 1980; Botvin 1982; Botvin 1983 (Intensive); Botvin 1983 (LST); Botvin 1999; Buller 2008 (USA); Coe 1982; Connell 2007; Elder 1996;  Ellickson 1990 (HealthEd); Ellickson 1990 (Teen); Ellickson 2003; Ennett 1994; Howard 1996; Johnson 2009; Kellam 1998 (GBG); Kellam 1998 (ML); Peterson 2000; Piper 2000 (HFL); Piper 2000 (HFL Age); Prokhorov 2008; Ringwalt 2009a; Simons‐Morton 2005; Spoth 2001 (ISFP); Spoth 2001 (PDFY); Spoth 2002 (LST); Spoth 2002 (LST + SFP); Storr 2002 (CC); Storr 2002 (FSP); Telch 1990 (No peers); Telch 1990 (Peers); Unger 2004 (CHIPS); Unger 2004 (FLAVOR); Valente 2007 (TND); Valente 2007 (TNDNetwork); Walter 1986