What do we know about preventing school violence? A systematic review of systematic reviews

Figures & data

Figure 1. PRISMA flowchart.

Table 1. Quality of reviews on intimate partner violence.

Review	AMSTAR score	No. of studies included in review	No. of school-based interventions included	No. of school-based interventions studied in RCTs
DeGue et al. (2014)	4	35	6	6
De Koker et al. (2014)	6	8	8	8
De La Rue et al. (2014)	10	23	23	10
Whitaker et al. (2006)	6	11	10	4
Whitaker et al. (2013)	4	9	4	4

Table 2. Intimate partner violence programmes assessed in RCTs with behavioral outcomes.

Programme	Target population, type of program and country of study	Implementer	No. of sessions and duration	Delivery mechanism
1. Dating Violence Prevention Program (Avery-leaf, Cascardi, O’Leary, & Cano, 1997)	11th and 12th grade students	Teachers	1 week	Psychoeducation on ‘courtship’ aggression
	Universal, discrete, specific
	Study conducted in New York
2. Safe Dates (Foshee et al., 1998, 2005, 2000, 1996)	8th and 9th grade students	Teachers	10 45-min sessions	Lecture, poster contest, peer theatre production;
	Universal, whole school, specific			Also includes a community component (crisis line, support groups, material for parents, training of service providers)
	Study conducted in North Carolina
3. Safe Dates with booster (Foshee et al., 2004)	This is a trial within the original trial, provided to randomly selected participants after the 2-year follow-up	Health educator	–	Newsletter containing information drawing on the Safe Dates curriculum; personal telephone call
	Universal, whole school, specific
4. Ending Violence (Jaycox et al., 2006)	9th grade students	Attorneys	3 days	Lecture and discussion of legal issues
	Universal, discrete, specific
	Study conducted in California
5. Stepping Stones (Jewkes et al., 2008)	Secondary school students	Project staff	50  for 6–8 weeks outside of school hours	Discussion, role-plays, drama
	Universal, discrete, comprehensive
	Study conducted in rural South Africa
6. Fourth R: Skills for Youth Relationships (Wolfe et al., 2009)	9th grade students	Teacher	21 sessions over 7 weeks	Videos, handouts, role-play
	Universal, discrete, comprehensive
	Study conducted in Canada
7. Law and Justice Curriculum (Taylor et al., 2010a, 2010b)	6th and 7th grade students	–	5 sessions	Knowledge-based curriculum
	Universal, discrete, specific
	Study conducted in Ohio
8. Interaction-based Treatment (Taylor et al., 2010a, 2010b)	6th and 7th grade students	–	5 sessions	Identifying unwanted behavior, setting boundaries, bystander intervention
	Universal, discrete, specific
	Study conducted in Ohio
9. Shifting Boundaries classroom-level (Taylor, Stein, Woods, & Mumford, 2011; Taylor et al., 2013)	6th and 7th grade students	Teachers	8 weeks	Lecture and discussion about identifying unwanted behavior and setting boundaries
	Universal, discrete, specific
	Study conducted in New York
10. Shifting Boundaries school-level (Taylor et al., 2011, 2013)	6th and 7th grade students	–	8 weeks	‘Building-based restraining orders’; school violence protocols with emphasis on reporting to teachers; awareness posters; student-created ‘hotspot’ map
	Universal, whole-school, comprehensive
	Study conducted in New York
11. Coaching Boys Into Men (Miller et al., 2013, 2012)	Male middle-school students in sports teams	Sports coaches	11 brief discussions (10–15 min) during sports season	Discussion
	Universal, discrete, specific
	Study conducted in the USA

Table 3. Effectiveness of intimate partner violence prevention programmes.

Programme	Follow-up period^a	Types of perpetration assessed	Types of victimisation assessed	Perpetration prevention	Victimisation prevention
1. Dating Violence Prevention Program (Avery-leaf et al., 1997)	Immediate post-test	Moderate physical aggression	–	No effect	–
2. Safe Dates (Foshee et al., 1998, 2005, 2000, 1996)	3 years	Moderate & severe physical; sexual; psychological violence	Moderate & severe physical; sexual; psychological violence	Effective at 2 years for all outcomes; at 3 years only for psychological and severe physical perpetration	Effective at 2 years for moderate physical and sexual victimisation; no effect at 3 years
3. Safe Dates with booster (tested against Safe Dates; Foshee et al., 2004)	3 years	Moderate & severe physical; sexual; psychological violence	Moderate & severe physical; sexual; psychological violence	Significant effect only for psychological perpetration	No effect
4. Ending Violence (Jaycox et al., 2006)	6 months	IPV	IPV	No effect	No effect
5. Stepping Stones (Jewkes et al., 2008)	1 year	Physical and sexual IPV, males	Physical and sexual IPV, females	Effective for perpetration by men at 2-year follow-up	No effect
6. Fourth R: Skills for Youth Relationships (Wolfe et al., 2009)	2.5 years	Moderate physical perpetration	–	Effective	–
7. Law and Justice Curriculum (Taylor et al., 2010a, 2010b)	6 months	Sexual violence	–	Increased reporting (possibly because of increased awareness)	–
8. Interaction-based Treatment (Taylor et al., 2010a, 2010b)	6 months	Sexual violence with dating partner	Sexual violence with dating partner	Increased reporting (possibly because of increased awareness)	No effect
9. Shifting Boundaries classroom-level (Taylor et al., 2011, 2013)	6 months	Prevalence and frequency of IPV	Prevalence and frequency of IPV	No effect	No effect
10. Shifting Boundaries school-level (Taylor et al., 2011, 2013)	6 months	Prevalence and frequency of IPV	Prevalence and frequency of IPV	No effect	Reductions in prevalence and frequency
11. Coaching Boys Into Men (Miller et al., 2013, 2012)	1 year	IPV perpetration	–	No effect	–

^a We report only the results from the longest possible follow-up period.

Table 4. Quality of reviews on peer aggression.

Review	AMSTAR score	No. of studies included in review	No. of studies with school-based intervention and effects for violence^a	No. of school-based studies using randomised controlled trials	No. of school-based studies using quasi-experimental designs
Allen-Meares, Montgomery, and Kim (2013)	3	18	3	1	2
Barnes, Smith, and Miller (2014)	4	25	20	13	7
Blank et al. (2010)	3	37	6	4	–
Bond, Woods, Humphrey, Symes, and Green (2013)	6	38	5	0	5
Bonell, Wells, et al. (2013)	7	10	4	3	1
Durlak, Weissberg, Dymnicki, Taylor, and Schellinger (2011)	5	213	112	–	–
Dymnicki, Weissberg, and Henry (2011)	4	26	26	–	–
Fagan and Catalano (2013)	4	18	9	7	2
Farahmand, Grant, Polo, Duffy, and DuBois (2011)	8	21	5	5	0
Gansle (2005)^b	4	27	22	–	–
Gavine, Donnelly, and Williams (2016)	7	16	12	7	5
Hahn et al. (2007)	7	65	65	–	14
Hale, Fitzgerald-Yau, and Mark Viner (2014)	6	50	8	8	–
Leff, Waasdorp, and Crick (2010)	4	10	9	7	2
Limbos et al. (2007)	5	41	22	–	–
Moestue, Moestue, and Muggah (2013)	5	18	4	3	1
Mytton, DiGuiseppi, Gough, Taylor, and Logan (2006)	8	51	34	34	0
Oliver, Reschly, and Wehby (2011)	4	12	4	4	0
Park-Higgerson, Perumean-Chaney, Bartolucci, Grimley, and Singh (2008)	5	26	26	26	0
Reddy, Newman, De Thomas, and Chun (2009)	9	29	22	4	18
Reese, Prout, Zirkelback, and Anderson (2010)^c	4	188	59	–	–
Sancassiani et al. (2015)	8	22	3	3	0
Schindler et al. (2015)	6	31	31	–	–
Sklad et al. (2012)	6	75	35	–	–
Stoltz et al. (2012)	6	24	24	18	6
Tolan et al. (2013)	9	46	3	–	–
Vidrine (n.d.)	6	10	10	8	2
Vreeman and Carroll (2007)	4	26	11	2	9
Wilson and Lipsey (2006a)	9	47	47	40	7
Wilson and Lipsey (2006b)	9	73	73	32	41
Wilson and Lipsey (2007)	9	399	249	158	91
Total	-	1692	963	387	213
Mean	5.93
Percentage^d				39.77%	21.89%

^a If the number of studies utilizing a randomised controlled trial design and quasi-experimental design do not equal the number of studies on school-based interventions for the same reviews, this study design information was not specified.

^b Figures based on the number of comparisons instead of the number of studies.

^c Figures based on the number of outcome measures instead of studies.

^d Total of column/total number of studies with school-based interventions.

Table 5. Characteristics of school-based programmes with effects on peer aggression.

Review	Prevention target (n; %)^a–c	Intervention approach (n; %)^a^,^b^,^d	Intervention content (n; %)^a^,^b^,^e	School level (n; %)^a^,^b^,^f	Participant gender (n; %)^a^,^b^,^g
Allen-Meares et al. (2013)	U (2; 67%)	W (0)	C (0)	PP (0)	M (0)
	S (1; 33%)	M(0)	S (0)	P (2; 67%)	F (0)
	I (0)	D (0)	NS (3; 100%)	H (0)	B (3; 100%)
	U & S (0)	NS (3; 100%)		C – PP & P (0)	NS (0)
	U & I (0)			C – P & H (1; 33%)
	S & I (0)			NS (0)
	NS (0)
Barnes et al. (2014)	U (14; 70%)	W (0)	C (0)	PP (0)	M (1; 5%)
	S (5; 25%)	M (0)	S (11; 55%)	P (19; 95%)	F (0)
	I (1; 5%)	D (20; 100%)	NS (9; 45%)	H (0)	B (19; 95%)
	U & S (0)	NS (0)		C – PP & P (0)	NS (0)
	U & I (0)			C – P & H (1; 5%)
	S & I (0)			C – (0)
	NS (0)			NS (0)
Blank et al. (2010)	U (6; 100%)	W (6; 100%)	C (0)	PP (0)	M (0)
	S (0)	M (0)	S (1; 17%)	P (0)	F (0)
	I (0)	D (0)	NS (5; 83%)	H (1; 17%)	B (5; 83%)
	U & S (0)	NS (0)		C – PP & P (0)	NS (1; 17%)
	U & I (0)			C – P & H (2; 33%)
	S & I (0)			C – (0)
	NS (0)			NS (3; 50%)
Bond et al. (2013)	U (0)	W (0)	C (3; 60%)	PP (0)	M (0)
	S (0)	M (3; 60%)	S (2; 40%)	P (3; 60%)	F (0)
	I (5; 100%)	D (2; 40%)	NS (0)	H (0)	B (5; 100%)
	U & S (0)	NS (0)		C – PP & P (0)	NS (0)
	U & I (0)			C – P & H (1; 20%)
	S & I (0)			C – (0)
	NS (0)			NS (1; 20%)
Bonell, Wells, et al. (2013)	U (4; 100%)	W (1; 25%)	C (0)	PP (0)	M (0)
	S (0)	M (0)	S (3; 89%)	P (2; 50%)	F (0)
	I (0)	D (3; 75%)	NS (1; 11%)	H (0)	B (4; 100%)
	U & S (0)	NS (0)		C – PP & P (1; 25%)	NS (0)
	U & I (0)
	S & I (0)			C – P & H (1; 25%)
	NS (0)			C – (0)
				NS (0)
Durlak et al. (2011)	U (112; 100%)	W (0)	C (0)	PP (0)	M (0)
	S (0)	M (0)	S (0)	P (0)	F (0)
	I (0)	D (0)	NS (112; 100%)	H (0)	B (0)
	U & S (0)	NS (112; 100%)		C – PP & P (0)	NS (112; 100%)
	U & I (0)			C – P & H (0)
	S & I (0)			C – (0)
	NS (0)			NS (112; 100%)
Dymnicki et al. (2011)	U (26; 100%)	W (0)	C (0)	PP (0)	M (0)
	S (0)	M (0)	S (0)	P (0)	F (0)
	I (0)	D (0)	NS (26; 100%)	H (0)	B (0)
	U & S (0)	NS (26; 100%)		C – PP & P (26; 100%)	NS (26; 100%)
	U & I (0)			C – P & H (0)
	S & I (0)			C – (0)
	NS (0)			NS (0)
Fagan and Catalano (2013)	U (2; 22%)	W (0)	C (0)	PP (2; 22%)	M (1; 11%)
	S (3; 33%)	M (7; 78%)	S (2; 22%)	P (6; 67%)	F (0)
	I (1; 12%)	D (2; 22%)	NS (7; 78%)	H (0)	B (8; 89%)
	U & S (3; 33%)	NS (0)		C – PP & P (0)	NS (0)
	U & I (0)			C – P & H (1; 11%)
	S & I (0)			C –(0)
	NS (0)			NS (0)
Farahmand et al. (2011)	U (2; 40%)	W (0)	C (0)	PP (0)	M (0)
	S (3; 60%)	M (0)	S (5; 100%)	P (4; 80%)	F (0)
	I (0)	D (0)	NS (0)	H (1; 20%)	B (5; 100%)
	U & S (0)	NS (5; 100%)		C – PP & P (0)	NS (0)
	U & I (0)			C – P & H (0)
	S & I (0)			C – (0)
	NS (0)			NS (0)
Gansle (2005)	U (0)	W (0)	C (0)	PP (0)	M (0)
	S (0)	M (0)	S (0)	P (0)	F (0)
	I (0)	D (0)	NS (22; 100%)	H (3; 15%)	B (0)
	U & S (0)	NS (22; 100%)		C – PP & P (7; 35%)	NS (20; 100%)
	U & I (0)			C – P & H (10; 50%)
	S & I (0)			C – (0)
	NS (22; 100%)			NS (0)
Gavine et al. (2016)	U (12; 100%)	W (0)	C (0)	PP (0)	M (0)
	S (0)	M (5; 42%)	S (0)	P (5; 42%)	F (0)
	I (0)	D (7; 58%)	NS (12; 100%)	H (2; 36%)	B (0)
	U & S (0)	NS (0)		C – PP & P (0)	NS (21; 100%)
	U & I (0)			C – P & H (5; 42%)
	S & I (0)			C – (0)
	NS (0)			NS (0)
Hale et al. (2014)	U (7; 78%)	W (2; 43%)	C (8; 100%)	PP (0)	M (0)
	S (1; 12%)	M (3;37)	S (0)	P (7; 87%)	F (0)
	I (0)	D (3; 37%)	NS (0)	H (0)	B (8; 100%)
	U & S (0)	NS (0)		C – PP & P (0)	NS (0)
	U & I (0)			C – P & H (1; 13%)
	S & I (0)			C – (0)
	NS (0)			NS (0)
Hahn et al. (2007)	U (65; 100%)	W (1; 2%)	C (0)	PP (0)	M (0)
	S (0)	M (0)	S (0)	P (34; 52%)	F (0)
	I (0)	D (0)	NS (65; 100%)	H (4; 6%)	B (0)
	U & S (0)	NS (64; 98%)		C – PP & P (6; 9%)	NS (65; 100%)
	U & I (0)			C – P & H (21; 33%)
	S & I (0)			C – (0)
	NS (0)			NS (53; 100%)
Leff et al. (2010)	U (6; 67%)	W (1; 11%)	C (0)	PP (1; 11%)	M (6; 67%)
	S (0)	M (2; 22%)	S (9; 100%)	P (5; 56%)	F (3; 33%)
	I (3; 33%)	D (6; 67%)	NS (0)	H (0)	B (0)
	U & S (0)	NS (0)		C – PP & P (2; 22%)	NS (0)
	U & I (0)			C – P & H (1; 11%)
	S & I (0)			C – (0)
	NS (0)			NS (0)
Limbos et al. (2007)	U (17; 77%)	W (0)	C (0)	PP (0)	M (0)
	S (5; 23%)	M (0)	S (0)	P (0)	F (0)
	I (0)	D (0)	NS (22; 100%)	H (2; 9%)	B (0)
	U & S (0)	NS (22; 100%)		C – PP & P (3; 14%)	NS (22; 100%)
	U & I(0)			C – P & H (16; 73%)
	S & I (0)			C – (1; 4%)
	NS (0)			NS (0)
Moestue et al. (2013)	U (3; 75%)	W (0)	C (0)	PP (0)	M (0)
	S (0)	M (1; 25%)	S (3; 75%)	P (1; 25%)	F (0)
	I (1; 25%)	D (3; 75%)	NS (1; 25%)	H (0)	B (4; 100%)
	U & S (0)	NS (0)		C – PP & P (1; 25%)	NS (0)
	U & I (0)			C – P & H (0)
	S & I (0)			C – (0)
	NS (0)			NS (2; 50%)
Mytton et al. (2006)h	U (0)	W (0)	C (0)	PP (0)	M (12; 35%)
	S (0)	M (0)	S (0)	P (22; 65%)	F (0)
	I (0)	D (0)	NS (34; 100%)	H (0)	B (22; 65%)
	U & S (0)	NS (34; 100%)		C – PP & P (0)	NS (0)
	U & I (0)			C – P & H (12; 35%)
	S & I (34; 100%)			C – (0)
	NS (0)			NS (0)
Oliver et al. (2011)	U (4; 100%)	W (0)	C (0)	PP (0)	M (0)
	S (0)	M (1; 25%)	S (4; 100%)	P (4; 100%)	F (0)
	I (0)	D (3; 75%)	NS (0)	H (0)	B (3; 75%)
	U & S (0)	NS (0)		C – PP & P (0)	NS (1; 25%)
	U & I (0)			C – P & H (0)
	S & I (0)			C – (0)
	NS (0)			NS (0)
Park-Higgerson et al. (2008)	U (7; 27%)	W (0)	C (7; 27%)	PP (0)	M (3; 11%)
	S (17; 65%)	M (10; 39%)	S (19; 73%)	P (19; 73%)	F (0)
	I (1; 4%)	D (16; 61%)	NS (0)	H (3; 11%)	B (23; 89%)
	U & S (1; 4%)	NS (0)		C – PP & P (2; 8%)	NS (0)
	U & I (0)			C – P & H (2; 8%)
	S & I (0)			C – (0)
	NS (0)			NS (0)
Reese et al. (2010)	U (0)	W (0)	C (0)	PP (0)	M (0)
	S (0)	M (0)	S (0)	P (0)	F (0)
	I (0)	D (0)	NS (59; 100%)	H (0)	B (0)
	U & S (0)	NS (59; 100%)		C – PP & P (0)	NS (59; 100%)
	U & I (0)			C – P & H (0)
	S & I (0)			C – (0)
	NS (59; 100%)			NS (59; 100%)
Reddy et al. (2009)	U (0)	W (0)	C (0)	PP (0)	M (0)
	S (8; 36%)	M (0)	S (0)	P (0)	F (0)
	I (14; 64%)	D (0)	NS (22; 100%)	H (0)	B (0)
	U & S (0)	NS (22; 100%)		C – PP & P (0)	NS (22; 100%)
	U & I (0)			C – P & H (0)
	S & I (0)			C – (0)
	NS (0)			NS (22; 100%)
Sancassiani et al. (2015)	U (3; 100%)	W (3; 100%)	C (2; 67%)	PP (0)	M (3; 100%)
	S (0)	M (0)	S (1; 33%)	P (2; 67%)	F (0)
	I (0)	D (0)	NS (0)	H (1; 33%)	B (0)
	U & S (0)	NS (0)		C – PP & P (0)	NS (0)
	U & I (0)			C – P & H (0)
	S & I (0)			C – (0)
	NS (0)			NS (0)
Schindler et al. (2015)	U (0)	W (0)	C (0)	PP (31; 100%)	M (0)
	S (0)	M (0)	S (0)	P (0)	F (0)
	I (0)	D (0)	NS (31; 100%)	H (0)	B (0)
	U & S (0)	NS (31; 100%)		C – PP & P (0)	NS (31; 100%)
	U & I (0)			C – P & H (0)
	S & I (0)			C – (0)
	NS (31; 100%)			NS (0)
Sklad et al. (2012)	U (35; 100%)	W (0)	C (0)	PP (0)	M (0)
	S (0)	M (0)	S (0)	P (0)	F (0)
	I (0)	D (0)	NS (35; 100%)	H (0)	B (0)
	U & S (0)	NS (35; 100%)		C – PP & P (0)	NS (35; 100%)
	U & I (0)			C – P & H (0)
	S & I (0)			C – (0)
	NS (0)			NS (35; 100%)
Stoltz et al. (2012)	U (0)	W (0)	C (0)	PP (2; 8%)	M (6; 25%)
	S (0)	M (13; 54%)	S (0)	P (15; 63%)	F (0)
	I (24; 100%)	D (11; 46%)	NS (24; 100%)	H (0)	B (18; 25%)
	U & S (0)	NS (0)		C – PP & P (5; 21%)	NS (0)
	U & I (0)			C – P & H (0)
	S & I (0)			C – (0)
	NS (0)			NS (2; 8%)
Tolan et al. (2013)	U (0)	W (0)	C (0)	PP (0)	M (0)
	S (2; 67%)	M (2; 67%)	S (0)	P (1; 33.33%)	F (0)
	I (1; 33%)	D (1; 33%)	NS (3; 100%)	H (1; 33.33%)	B (2; 67%)
	U & S (0)	NS (0)		C – PP & P (0)	NS (1; 33%)
	U & I (0)			C – P & H (1; 33.33%)
	S & I (0)			C – (0)
	NS (0)			NS (0)
Vidrine (n.d.)	U (0)	W (0)	C (0)	PP (6; 60%)	M (0)
	S (0)	M (0)	S (10; 100%)	P (4; 40%)	F (0)
	I (0)	D (0)	NS (0)	H (0)	B (10; 100%)
	U & S (0)	NS (10; 100%)		C – PP & P (0)	NS (0)
	U & I (0)			C – P & H (0)
	S & I (0)			C – (0)
	NS (10; 100%)			NS (0)
Vreeman and Carroll (2007)	U (5; 46%)	W (3; 27%)	C (2; 18%)	PP (0)	M (0)
	S (3; 27%)	M (2; 18%)	S (9; 82%)	P (6; 55%)	F (1; 9%)
	I (1; 9%)	D (6; 55%)	NS (0)	H (1; 9%)	B (10; 91%)
	U & S (0)	NS (0)		C – PP & P (0)	NS (0)
	U & I (1; 9%)			C – P & H (4; 36%)
	S & I (0)			C – (0)
	NS (1; 9%)			NS (0)
Wilson and Lipsey (2006b)	U (73; 100%)	W (0)	C (0)	PP (14; 19%)	M (8; 11%)
	S (0)	M (0)	S (0)	P (47; 64%)	F (6; 8%)
	I (0)	D (0)	NS (73; 100%)	H (12; 16%)	B (59; 81%)
	U & S (0)	NS (73; 100%)		C – PP & P (0)	NS (0)
	U & I (0)			C – P & H (0)
	S & I (0)			C – (0)
	NS (0)			NS (0)
Wilson and Lipsey (2006a)	U (0)	W (0)	C (0)	PP (0)	M (14; 30%)
	S (17; 36%)	M (0)	S (0)	P (31; 66%)	F (1; 2%)
	I (30; 64%)	D (0)	NS (47; 100%)	H (16; 34%)	B (32; 68%)
	U & S (0)	NS (47; 100%)		C – PP & P (0)	NS (0)
	U & I (0)			C – P & H (0)
	S & I (0)			C – (0)
	NS (0)			NS (0)
Wilson and Lipsey (2007)	U (89; 36%)	W (0)	C (0)	PP (0)	M (43; 17%)
	S (0)	M (21; 8%)	S (0)	P (178; 72%)	F (17; 7%)
	I (0)	D (228; 92%)	NS (249; 100%)	H (50; 20%)	B (179; 72%)
	U & S (0)	NS (0)		C – PP & P (21; 8%)	NS (10; 4%)
	U & I (0)			C – P & H (0)
	S & I (117; 47%)			C – (0)
	NS (43; 17%)			NS (0)
Total across reviews	U (494; 51.30%)	W (17; 1.77%)	C (22; 2.28%)	PP (56; 5.82%)	M (88; 9.14%)
	S (65; 6.75%)	M (70; 7.27%)	S (79; 8.20%)	P (417; 43.30%)	F (28; 2.91%)
	I (81; 8.41%)	D (311; 32.29%)	NS (862; 89.51%)	H (94; 9.76%)	B (440; 45.69%)
	U & S (5; 0.52%)	NS (565; 58.67%)		C – PP & P (68; 7.06%)	NS (407; 42.26%)
	U & I (1; 0.10%)			C – P & H (69; 7.17%)
	S & I (151; 15.68%)			C – (1; 0.10%)
	NS (166; 17.24%)			NS (258; 26.79%)

^a % = number of studies on school-based interventions with effects for peer aggression with characteristic/total number of studies on school-based interventions with effects for peer aggression.

^b NS = not specified.

^c U = universal, S = selected, I = indicated.

^d W = whole-school, M = multilevel, D = discrete.

^e C = comprehensive, S = specific.

^f PP = pre-primary school, P = primary school, H = high school.

^g F = female-only participants, M = male-only participants, B = participants of both genders.

^h All descriptives and effects reflect studies using measures of the level or extent of actual aggressive behavior or physical acts of aggression, either observed or reported only.

Table 6. No of studies by country, by WHO regions.

WHO regions	No. of studies
North America (total)^a	562
USA	527
Canada	35
Europe (total)	14
UK	6
Italy	2
Norway	2
Israel	1
Netherlands	1
Finland	1
Spain	1
South America (total)	7
Argentina	2
Columbia	2
Brazil	1
Jamaica	1
Mexico	1
Western Pacific (total)	7
Australia	6
China	1
South East Asia (total)	1
India	1
Africa (total)	0
Eastern Mediterranean (total)	0
Not Specified	372
Total Relevant Studies	963

^a We decided to split the Americas region into two: North (USA and Canada) and South (all other countries in the Americas), because of the vastly disproportionate amount of research typically conducted in North America.

Figure 2. WHO regions covered by peer aggression programmes.

Table 7. Effectiveness of peer aggression programmes to prevent victimisation.

Review	Prevention target				Intervention approach				Harmful effects	Outcome behavior^a	Significant moderators
	Universal: PT^b/FU^c/NS^d: E^e (n)^f^/^g	Selected: PT^b/FU^c/NS^d: E^e (n)^f^/^g	Indicated: PT^b/FU^c/NS^d: E^e (n)^f^/^g	Not specified: PT^b/FU^c/NS^d: E^e (n)^f^/^g	Whole-school: PT^b/FU^c/NS^d: E^e (n)^f^/^g – IT^h	Multi-level: PT^b/FU^c/NS^d: E^e (n)^f^/^g – IT^h	Discrete: PT^b/FU^c/NS^d: E^e (n)^f^/^g – IT^h	Not specified: PT^b/FU^c/NS^d: E^e (n)^f^/^g – IT^h
Barnes et al. (2014)	NS:1 (1)^f						NS:1 (1)^f – 5		No	4	Prevention target (universal vs selected)
Blank et al. (2010)^i	NS: 7 (1)^f				NS: 7 (1)^f – 10				No	1	Not considered
Bonell, Wells, et al.(2013)	PT: 5 (2)^f						PT: 5 (2)^f – 9		No	1; 2; 3; 4	Not considered
	FU: 7 (1)^f						FU: 7 (1)^f – 9
Gavine et al. (2016)^j	FU: 7 (1)^f					FU: 7 (1) – 1	NS: 6 (2)^f – 1		No	1; 2; 3; 4	Not considered
	NS: 5 (3)^f					NS: 4 (1) – 1
Hale et al. (2014)	FU: 4 (1)^f						FU: 4 (1)^f – 9		No	2	Not considered
Leff et al. (2010)	NS: 1 (2)^f				NS: 1 (1)^f – 1		NS: 1 (1)^f – 1		No	2; 4	Not considered
Sancassiani et al. (2015)	PT: 7 (1)^f				PT: 7 (1)^f – 4				No	1	Not considered
Vreeman and Carroll (2007)^k		PT: 7 (1)^f					PT: 7 (1)^f – 4		No	1	Not considered

^a 1 – Victimisation (specific type not specified); 2 – Physical victimsation; 3 – Verbal victimisation; 4 – Relational victimization.

^b Post-test effects.

^c Follow-up effects.

^d Post-test or follow-up measurement was not specified in review.

^e Effectiveness rating based on rubric. We rated the effectiveness of interventions reviewed according to the following rubric: (1) Found overall to be effective (i.e. peer aggression reduced in 100% of the effects, or as reported by a meta-analysis); (2) Found to be mostly effective (i.e. peer aggression reduced in 75% or more of the reviewed studies’ effects as a result of the intervention); (3) Found to be slightly effective (i.e. peer aggression reduced in 56–74% of the reviewed studies’ effects as a result of the intervention); (4) Overall mixed effects (i.e. peer aggression reduced in 45–55% of the reviewed studies’ effects as a result of the intervention); (5) A minority of studies found an effect (i.e. peer aggression reduced in 26–44% of the reviewed studies’ effects as a result of the intervention); (6) Found to be mostly ineffective (i.e. peer aggression reduced in 25% or less of the reviewed studies’ effects as a result of the intervention); (7) Found overall to be ineffective (i.e. no effects/change on peer aggression overall, or as reported by a meta-analysis).

^f Number of primary studies used in calculating effect.

^g Based on effect derived from meta-analysis.

^h Intervention type: 1 – Violence prevention programmes (also includes conflict training, modified discipline, anger management); 2 – Classroom management programmes; 3 – Life skills programmes (also includes problem solving skills training, perspective taking skills training and coping skills training); 4 – Social-emotional programmes (also includes social skills programmes); 5 – Cognitive behavioral interventions (also includes cognitive interventions and interventions for behavior modification) or social cognitive interventions; 6 – Peer mediators or mentoring; 7 – ECD/ECE; 8 – Combined; 9 – Other; 10 – Not specified.

ⁱ Many study outcomes were not clear. Only the studies that explicitly discussed school-based interventions for the outcomes of interest were considered.

^j Conservatively coded as multilevel instead of whole-school because they did not indicate at which levels they intervened.

^k Effects for victimization were only extracted for studies which did not also have effects on bullying as it was assumed the victimization would relate to bullying instead of peer aggression.

Table 8. Effectiveness of peer aggression programmes to prevent perpetration.

Review	Prevention target				Intervention approach				Harmful effects	Outcome behavior^a	Significant moderators
	Universal: PT^b/FU^c/NS^d: E^e (n)^f^/^g	Selected: PT^b/FU^c/NS^d: E^e (n)^f^/^g	Indicated: PT^b/FU^c/NS^d: E^e (n)^f^/^g	Not specified: PT^b/FU^c/NS^d: E^e (n)^f^/^g	Whole-school: PT^b/FU^c/NS^d: E^e (n)^f^/^g – IT^h	Multi-level: PT^b/FU^c/NS^d: E^e (n)^f^/^g – IT^h	Discrete: PT^b/FU^c/NS^d: E^e (n)^f^/^g – IT^h	Not specified: PT^b/FU^c/NS^d: E^e (n)^f^/^g – IT^h
Allen-Meares et al. (2013)	NS:1 (2)^f	PT: 1 (1)^f						NS: 1 (2)^f −5	No	1; 4	Not considered
								PT: 1 (1)^f – 9
Barnes et al. (2014)	NS:3 (15)^f	NS: 3 (6)^f					NS: 3 (20)^f – 5		Yes	1; 2; 4	Prevention target (universal vs selected)
Blank et al. (2010)^i	NS: 3 (6)^f				NS: 1 (2)^f – 3				No	1	Not considered
					NS: 3 (4)^f – 10
Bond et al. (2013)^i			PT: 2 (5)^f			PT: 2 (3)^f – 9	PT: 1 (2)^f – 9		No	1; 4	Not considered
							FU: 1 (1)^f – 9
			FU: 1 (3)^f			FU: 1 (2)^f – 9
Bonell, Wells, et al. (2013)	PT: 5 (2)^f				FU: 7 (1)^f – 9		PT: 5 (2)^f – 9		No	1; 2	Not considered
	FU: 6 (3)^f						FU: 5 (2)^f – 9
Durlak et al. (2011)	PT: 1 (112)^gFU: 1 (21)^g							PT: 1 (112)^g – 4	No	3 (including 1)	None
								FU: 1 (21)^g – 4
Dymnicki et al. (2011)	PT: 1 (26)^g							PT: 1 (26)^g – 1	Yes	1	Not considered
Fagan and Catalano (2013)^j	PT: 4 (3)^f	FU: 3 (4)^f	PT: 4 (1)^f	PT: 1 (1)^f		FU: 3 (2)^f – 7	PT: 4 (1)^f – 1		Yes	1	Not considered
						PT: 4 (3)^f – 8
				FU: 4 (1)^f		FU: 3 (3)^f – 8	PT: 1 (1)^f – 4
Farahmand et al. (2011)^i	PT: 4 (2)^f	PT: 6 (3)^f						PT: 5 (5)^f – 9	Yes	4	Not considered
	FU: 7 (1)^f	FU: 7 (1)^f						FU: 7 (2)^f – 9
Gansle (2005) ^k				PT: 1 (22)^g				PT: 1 (22)^g – 1; 4; 5	No	4 (including 1 and 3)	Random assignment and treatment duration^l
				FU: 1 (9)^g				FU: 1 (9)^g – 1; 4; 5
Gavine et al. (2016)^m	PT: 5 (2)^f					PT: 7 (1)^f – 1	PT: 1 (1)^f – 1		Yes	1	Not considered
	FU: 5 (4)^f					FU: 6 (2)^f – 1	NS: 4 (3)^f – 1
	NS: 5 (7)^f					NS: 5 (3)^f – 1	FU: 3 (1)^f – 3
							FU: 6 (1)^f – 9
							NS: 1 (1)^f – 9
Hahn et al. (2007)^n	NS: 1 (65)^g							NS: 1 (30)^g – 4	No	1; 2; 3; 4	Not considered
								NS: 1 (6)^g – 5
								NS: 1 (2)^g – 6
								NS: 1 (25)^g – 9
Hale et al. (2014)	PT: 1 (2)^f	PT: 1 (1)^f			PT: 1 (1)^f – 4	PT: 1 (1)^f – 5	PT: 1 (1)^f – 4		No	1	Not considered
					FU: 1 (1)^f – 9	FU: 1 (1)^f – 8
	FU: 1 (4)^f					FU: 1 (1)^f – 9	FU: 1 (1)^f – 9
Leff et al. (2010)	PT: 5 (4)^f		NS: 1 (3)^f			NS: 1 (2)^f – 5	PT: 4 (2)^f – 1		No	1; 2	Not considered
							NS: 1 (1)^f – 1
	NS: 1 (1)^f						PT: 7 (1)^f – 2
							PT: 1 (1)^f – 4
							NS: 1 (1)^f – 5
Limbos et al. (2007)^o	NS: 5 (17)^f	NS: 5 (5)^f						NS: 5 (22)^f – 1	No	1	Not considered
Moestue et al. (2013)	PT: 1 (3)^f		NS: 1 (1)^f			PT: 1 (1)^f – 1	NS: 1 (1)^f – 2		No	1; 3	Not considered
							PT: 1 (1)^f – 4
							PT: 1 (1)^f – 9
Mytton et al. (2006)^p		PT: 1 (34)^g						PT: 1 (18)^g – 1	No	1	School level
								FU: 1 (2)^g – 1
								PT: 1 (7)^g – 4/6
		FU: 1 (7)^g
								FU: 7 (2)^g – 4/6
								PT: 1 (7)^g – 8
								FU: 7 (3)^g – 8
Oliver et al. (2011)^q	PT: 6 (4)^f					PT: 7 (1)^f – 2	PT: 5 (3)^f – 2		No	1; 3; 4	Not analyzed
Park-Higgerson et al. (2008)^r	PT: 2 (4)^f	PT: 4 (16)^f	PT: 4 (1)^f			PT: 5 (4)^f – 5	PT: 1 (1)^f – 1		No	1; 2; 4	Not considered
						FU: 5 (2)^f – 5	PT: 1 (1)^f – 2
						PT: 7 (1)^f – 8	FU: 7 (1)^f – 3
						FU: 7 (1)^f – 8	PT: 4 (4)^f – 5
	FU: 5 (4)^f	FU: 5 (4)^f	FU: 4 (1)^f			PT: 1 (2)^f – 9	FU: 5 (3)^f – 5
						PT: 7 (1)^f – 10	PT: 2 (3)^f – 8
							FU: 5 (1)^f – 8
							PT: 1 (5)^f – 9
Reddy et al. (2009)		PT: 1 (8)^g	PT: 1 (12)^g					PT: 1 (22)^g– 10	No	4	No analysis completed
		FU: 1 (3)^g	FU: 1 (3)^g					FU: 1 (22)^g– 10
Reese et al. (2010)^s				PT: 1 (59)^g				PT: 1 (59)^g – 9	No	4	No analysis completed
Sancassiani et al. (2015)	PT: 3 (2)^f				PT: 7 (1)^f – 3				No	1; 3	Not considered
					PT: 1 (1)^f – 4
Schindler et al. (2015)				PT: 7 (31)^g				PT: 7 (31)^g – 7	No	4 (including 1)	Extent of focus on socio-emotional development
Sklad et al. (2012)^t	PT: 1 (35)^g							PT: 1 (35)^g – 4/5	No	1; 4	Duration of program, school level.
	FU: 1 (35)^g							FU: 1 (35)^g – 4/5
Stoltz et al. (2012)^u			PT: 1 (24)^g			PT: 1 (13)^g – 5	PT: 1 (11)^g – 5		Yes	4 (including 1, 2 and 3)	Age of participants
Tolan et al. (2013)		NS: 4 (2)^f	NS: 7 (1)^f			NS: 4 (2)^f – 6	NS: 7 (1)^f – 6		No	1	Not considered
Vidrine (n.d.)^v				FU: 1 (10)^g				FU: 1 (10)^g – 3	No	4 (including 1 and 2)	Age of participants
Vreeman and Carroll (2007)^w	PT: 3 (4)^f	PT: 1 (2)^f	NS: 7 (1)^f	PT: 1 (1)^f	PT: 2 (2)^f – 6	PT: 7 (1)^f – 5	PT: 1 (1)^f – 3		Yes	1; 2; 4	Not considered
							PT: 4 (2)^f – 4
			Combination U&I				PT: 1 (1)^f – 6
							NS: 7 (1)^f – 6
	NS: 7 (1)^f				NS: 7 (1)^f – 10	PT: 1 (1)^f – 9
			PT: 5 (1)^f
Wilson and Lipsey (2006b)^x	PT: 1 (73)^g							PT: 1 (73)^g ^– 5	No	1; 3; 4	Socioeconomic status, routine practice, frequency of sessions, implementation quality
Wilson and Lipsey (2006a)^y			PT: 1 (47)^g					PT: 1 (47)^g – 5	No	1; 3; 4	Attrition, special education
S. J. Wilson and Lipsey (2007)^z	PT: 1 (77)^g	PT: 1 (108)^g		PT: 7 (43)^g		PT: 7 (21)^g ^– 4/5/6/9	PT: 3 (228)^g ^– 4/5/6/9		No	1; 3	Student socio-economic status, attrition, student risk level, implementation quality

^a 1 – Aggression and/or violence (physical aggression/violence, physical fights or attacks, verbal aggression); 2 – Relational aggression; 3 – Conduct problems/disorder; 4 – Externalizing behaviors.

^b Post-test effects.

^c Follow-up effects.

^d Post-test or follow-up measurement was not specified in review.

^e Effectiveness rating based on rubric. We rated the effectiveness of interventions reviewed according to the following rubric: (1) Found overall to be effective (i.e. peer aggression reduced in 100% of the effects, or as reported by a meta-analysis); (2) Found to be mostly effective (i.e. peer aggression reduced in 75% or more of the reviewed studies’ effects as a result of the intervention); (3) Found to be slightly effective (i.e. peer aggression reduced in 56–74% of the reviewed studies’ effects as a result of the intervention); (4) Overall mixed effects (i.e. peer aggression reduced in 45–55% of the reviewed studies’ effects as a result of the intervention); (5) A minority of studies found an effect (i.e. peer aggression reduced in 26–44% of the reviewed studies’ effects as a result of the intervention); (6) Found to be mostly ineffective (i.e. peer aggression reduced in 25% or less of the reviewed studies’ effects as a result of the intervention); (7) Found overall to be ineffective (i.e. no effects/change on peer aggression overall, or as reported by a meta-analysis).

^f Number of primary studies used in calculating effect.

^g Based on effect derived from meta-analysis.

^h Intervention type: 1 – Violence prevention programmes (also includes conflict training, modified discipline, anger management); 2 – Classroom management programmes; 3 – Life skills programmes (also includes problem solving skills training, perspective taking skills training and coping skills training); 4 – Social-emotional programmes (also includes social skills programmes); 5 – Cognitive behavioral interventions (also includes cognitive interventions and interventions for behavior modification) or social cognitive interventions; 6 – Peer mediators or mentoring; 7 – ECD/ECE; 8 – Combined; 9 – Other; 10 – Not specified.

ⁱ Many study outcomes were not clear. Only the studies that explicitly discussed school-based interventions for the outcomes of interest were considered.

^j Effects in not specified column represent combined universal and selective programmes.

^k Figures based on the number of comparisons instead of the number of studies.

^l Not strictly moderators, but considered their correlation with effect size.

^m Conservatively coded as multilevel instead of whole-school because they did not indicate at which levels they intervened.

ⁿ In this review, violence refers to both victimization and perpetration. Placed effects in perpetration table only as these seemed to be more common, and their studies likely followed this trend.

^o Review provides unconservative estimates of a study’s effectiveness. Each study only needed one positive effect to be considered effective overall.

^p All descriptives and effects reflect studies using measures of the level or extent of actual aggressive behavior or physical acts of aggression, either observed or reported only.

^q Utilized the effects of the ICC.10 analysis only in determining effectiveness.

^r Selected interventions seemed to included indicated samples at times, we relied on their classification.

^s Figures based on the number of outcome measures instead of studies.

^t Post-test considered effects up to and including 6 months after completion of the intervention. Follow-up included outcomes measured at least 7 months after completion of an intervention.

^u The multilevel number might be inflated due to this review not separating whole-school interventions.

^v Effects based on most distal results.

^w Coded post-test and follow-up information according to their study design information.

^x Only 74% of the included studies had effects at immediate post-test, thus our results are coded as post-test overall.

^y Results thought to be most reflective of post-test findings, and selected and indicated intervention effects were combined. There were more indicated than selected interventions, so effects were placed under the former column.

^z Could not isolate all effects for universal programmes and selected/indicated programmes. As subject risk was selected (42%) and indicated (19%), effects for selected/indicated interventions were thought to be more reflective of selective interventions, thus they were placed under this category. Effects with p < .10 were not considered effective in our analysis.

Table

EBSCOHost databases

Academic Search Premier

Business Source Premier

Africa-Wide Information

AHFS Consumer Medication Information

ATLA Religion Database with ATLASerials

CINAHL

Communication & Mass Media Complete

ERIC

Health Source: Nursing/Academic Edition

Humanities International Complete

International Bibliography of Theatre & Dance with Full Text

Library, Information Science & Technology Abstracts

MasterFILE Premier

MEDLINE

Philosopher’s Index

PsycARTICLES

PsycCRITIQUES

PsycINFO

PsycTESTS

SocINDEX with Full Text

Teacher Reference Center

ProQuest databases

Environment Abstracts

ERIC

International Bibliography of the Social Sciences (IBSS)

International Index to Performing Arts Full Text

Library and information Science Abstracts (LISA)

PAIS International and PAIS archive

PILOTS: Published International Literature On Traumatic Stress

ProQuest Education Journals

Social Services Abstracts

Sociological Abstracts

OCLC FirstSearch

Medline

ERIC

PubMed

Medline

Wiley Online Library

Sage Journals Online – 2014 Premier Package

Web of Science

Africa Bibliography

British Education Index- the free collections

ERIC (directly at eric.ed.gov)

Cochrane Library

Campbell Collaboration Libraries

Open Grey

BDENF

Global Health

HISA

LILACS

MedCarib

WPRIM

Table

Trial registries

Clinical Trials Registry: www.clinicaltrials.gov

The Pan-African Clinical Trials Registry: http://www.pactr.org/

The WHO violence prevention trials registry: http://www.preventviolence.info/Trials

Table

Hand search journals
Aggression and Violent Behavior
International Journal of Violence and schools
Journal of School Violence
Journal of Injury and Violence Research
Youth Violence and Juvenile Justice
Violence and Victims
Journal of Aggression, Maltreatment and Trauma
The School Community Journal
Journal of School Health
Journal of Interpersonal Violence
Journal of School Psychology
Journal of Educational Psychology
School Psychology Quarterly
Journal of Applied School Psychology
Contemporary School Psychology
Psychology in the Schools
British Journal of Educational Psychology
School Psychology International
School Psychology Review
Educational Psychology

Table

Review	Reason for exclusion
Barlow, Smailagic, Ferriter, Bennett, and Jones (2010)	Too few school-based studies on outcomes of interest included
Baskin et al. (2010)	Unclear if outcomes of interest were included in review, and if they were to what extent
Beelmann and Raabe (2009)	Review of reviews
Bonell et al. (2013)	Protocol of a review, not an actual review
Bowman-Perrott, Burke, Nan, and Zaini (2014)	Too few school-based studies on outcomes of interest included
Candelaria, Fedewa, and Ahn (2012)	Could not clearly determine all of the studies which were school-based and which considered outcomes of interest
Cobb, Sample, Morgen, and Johns (2006)	Could not clearly determine all of the studies which were school-based and which considered outcomes of interest
Edwards and Hinsz (2014)	Too few school-based studies on outcomes of interest included
Ehiri, Hitchcock, Ejere, and Mytton (2007)	Protocol of a review, not an actual review
Fellmeth, Heffernan, Nurse, Habibula, and Sethi (2013)	Could not clearly determine which studies that were included in analysis were school-based
Ferguson, Miguel, Kilburn, and Sanchez (2007)	Effects for bullying and other types of violence were not reported separately. Could not determine extent to which violence outside of bullying was represented in statistics
Grove, Evans, Pastor, and Mack (2008)	Could not clearly determine how many school-based interventions were included, and thus how represented they were in the statistics
R. Hahn et al. (2007)	A published version of this report was also found in our searches and thus used instead.
R. A. Hahn et al. (2005)	Too few school-based studies on outcomes of interest included
Hankin, Hertz, and Simon (2011)	Too few school-based studies on outcomes of interest included
January, Casey, and Paulson (2011)	No clear effects on outcome behaviors of interest i.e., there was no way to determine to what extent aggression was an outcome which was considered in included studies and thus how represented it was in the analysis
Klasen and Crombag (2013)	Too few school-based studies on outcomes of interest included
Kristjansson et al. (2006)	Too few school-based studies on outcomes of interest included
D. M. Maggin, Chafouleas, Goddard, and Johnson (2011)	Did not consider outcomes of interest
Daniel M. Maggin, Johnson, Chafouleas, Ruberto, and Berggren (2012)	Outcome behaviors of interest comprised less than 5% of outcome behaviors considered in review. No way of determining the effects specific to outcome behaviors of interest either
Matjasko et al. (2012)	Review of reviews
McCart, Priester, Davies, and Azen (2006)	School-based intervention effects could not be separated from the effects for interventions implemented elsewhere. No way of knowing how many school-based interventions were included either
Meirelles dos Santos and Giglio (2012)	Too few school-based studies on outcomes of interest included
Montgomery and Maunders (2015)	Too few school-based studies on outcomes of interest included
Ozabaci (2011)	Too few school-based studies on outcomes of interest included
Parker and Turner (2013)	Too few school-based studies on outcomes of interest included
Piquero et al. (2008)	Too few school-based studies on outcomes of interest included
Piquero, Jennings, Farrington, and Jennings (2010)	Unclear to what extent outcomes of interest were included and separating school-based effects was impossible to do
Polanin and Espelage (2015)	Primary study
Reichow, Barton, Boyd, and Hume (2014)	Did not consider outcomes of interest
Sentenac et al. (2012)	Too few school-based studies on outcomes of interest included
Silverman et al. (2008)	Too few school-based studies on outcomes of interest included
Singh et al. (2011)	Too few school-based studies on outcomes of interest included
Solomon, Klein, Hintze, Cressey, and Peller (2012)	Unclear to what extent outcomes of interest are included and represented in statistics
Sugimoto-Matsuda and Braun (2014)	Did not consider outcomes of interest.
Ting (2009)	Did not consider outcomes of interest
Vannest, Davis, Davis, Mason, and Burke (2010)	No distinct separation of the effects for the outcome behaviors of interest and other behaviors
Walsh, Zwi, Woolfenden, and Shlonsky (2015)	Too few school-based studies on outcomes of interest included
Weisburd, Telep, Hinkle, and Eck (2008)	Too few school-based studies on outcomes of interest included
Wilson and Institute for Public Policy Studies (2005)	Showed significant similarity to Wilson and Lipsey (2007) article. Later article was chosen to be included in review as it included a greater number of studies and was published more recently

Table

			Yes	No	Can’t answer	Comments
1.	Question:	Was an ‘a priori’ design provided?
	Explanation:	The research question and inclusion criteria should be established before the conduct of the review
	Note:	Need to refer to a protocol, ethics approval, or pre-determined/a priori published research objectives to score a ‘yes’
2.	Question:	Was there duplicate study selection and data extraction?
	Explanation:	There should be at least two independent data extractors and a consensus procedure for disagreements should be in place
	Note:	Two people do study selection, two people do data extraction, consensus process or one person checks the other’s work
3.	Question:	Was a comprehensive literature search performed?
	Explanation:	At least two electronic sources should be searched. The report must include years and databases used (e.g. Central, EMBASE, and MEDLINE). Key words and/or MESH terms must be stated and where feasible the search strategy should be provided. All searches should be supplemented by consulting current contents, reviews, textbooks, specialized registers, or experts in the particular field of study, and by reviewing the references in the studies found
	Note:	If at least two sources + one supplementary strategy used, select ‘yes’ (Cochrane register/central counts as two sources; a grey literature search counts as supplementary)
4.	Question:	Was the status of publication (i.e. grey literature) used as an inclusion criterion?
	Explanation:	The authors should state that they searched for reports regardless of their publication type. The authors should state whether or not they excluded any reports (from the systematic review), based on their publication status, language etc.
	Note:	If review indicates that there was a search for ‘grey literature’ or ‘unpublished literature’, indicate ‘yes’. SIGLE database, dissertations, conference proceedings, and trial registries are all considered grey for this purpose. If searching a source that contains both grey and non-grey, must specify that they were searching for grey/unpublished lit
5.	Question:	Was a list of studies (included and excluded) provided?
	Explanation:	A list of included and excluded studies should be provided.
	Note:	Acceptable if the excluded studies are referenced. If there is an electronic link to the list but the link is dead, select ‘no’
6.	Question:	Were the characteristics of the included studies provided?
	Explanation:	In an aggregated form such as a table, data from the original studies should be provided on the participants, interventions and outcomes. The ranges of characteristics in all the studies analyzed e.g., age, race, sex, relevant socioeconomic data, disease status, duration, severity, or other diseases should be reported
	Note:	Acceptable if not in table format as long as they are described as above
7.	Question:	Was the scientific quality of the included studies assessed and documented?
	Explanation:	‘A priori’ methods of assessment should be provided (e.g. for effectiveness studies if the author(s) chose to include only randomized, double-blind, placebo controlled studies, or allocation concealment as inclusion criteria); for other types of studies alternative items will be relevant
	Note:	Can include use of a quality scoring tool or checklist, e.g., Jadad scale, risk of bias, sensitivity analysis, etc., or a description of quality items, with some kind of result for EACH study (‘low’ or ‘high’ is fine, as long as it is clear which studies scored ‘low’ and which scored ‘high’; a summary score/range for all studies is not acceptable)
8.	Question:	Was the scientific quality of the included studies used appropriately in formulating conclusions?
	Explanation:	The results of the methodological rigor and scientific quality should be considered in the analysis and the conclusions of the review, and explicitly stated in formulating recommendations
	Note:	Might say something such as ‘the results should be interpreted with caution due to poor quality of included studies’. Cannot score ‘yes’ for this question if scored ‘no’ for question 7
9.	Question:	Were the methods used to combine the findings of studies appropriate?
	Explanation:	For the pooled results, a test should be done to ensure the studies were combinable, to assess their homogeneity (i.e. Chi-squared test for homogeneity, I^2 ). If heterogeneity exists a random effects model should be used and/or the clinical appropriateness of combining should be taken into consideration (i.e. is it sensible to combine?)
10.	Note:	Indicate ‘yes’ if they mention or describe heterogeneity, i.e., if they explain that they cannot pool because of heterogeneity/variability between interventions
	Question:	Was the likelihood of publication bias assessed?
11.	Explanation:	An assessment of publication bias should include a combination of graphical aids (e.g. funnel plot, other available tests) and/or statistical tests (e.g. Egger regression test, Hedges-Olken)
	Note:	If no test values or funnel plot included, score ‘no’. Score ‘yes’ if mentions that publication bias could not be assessed because there were fewer than 10 included studies.
	Question:	Was the conflict of interest included?
	Explanation:	Potential sources of support should be clearly acknowledged in both the systematic review and the included studies
	Note:	To get a ‘yes’, must indicate source of funding or support for the systematic review AND for each of the included studies
		Total AMSTAR Score:

Table

1.	No. of studies in review	Not specified
2.	No. of studies on school-based interventions with violent behavior as an outcome	Not specified
3.	No. of studies on school-based interventions with ONLY attitudes towards violence as an outcome	Not specified

Table

Prevention target		Characteristic relevant	No. of primary studies
1	Universal only
2	Selected only
3	Indicated only
4	Combination
5	Not specified
Approach
1	Whole-school only
2	Discrete only
3	Combination
4	Not specified
Content
1	Comprehensive only
2	Specific only
3	Combination
4	Not specified
School level
1	Pre-primary only
2	Primary only
3	High only
4	Combination PP + P
5	Combination P + H
6	Combination all
7	Not specified
Participant gender
1	Female-only
2	Male-only
3	Mixed
4	Not specified
Study design
1	Randomised controlled trial
2	Quasi-experimental
3	Not specified
WHO regions		Characteristic relevant	No. of primary studies for each country in region
1	North America
2	South America
3	Western Pacific
4	Europe
5	Eastern Mediterranean
6	Africa
7	South East Asia
8	Not specified

Table

Reduction in violence (effective)	No effect on violence (ineffective)	Increase in violence (harmful)

Table

No.	Primary study name	Reduction in violence (effective)	No effect on violence (ineffective)	Increase in violence (harmful)
1
2
3
4
5
6
7
	Sub-totals:
Grand total number of effects:

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