<p> Supplementary material: True love: effectiveness of a school-based program to reduce partner violence among teenagers in Mexico City. Table S1. Propensity Score Matching: Bias correction</p><p>U=unmatche Mean % reduct. | t-test d bias| Variable M=matched SCC, IL-1 SCC %Bias t p>|t| Individual Characteristics U 15.99 16.28 -23.0 -3.490 0.000 Age (mean) M 16.032 16.04 -0.3 9.88 -0.040 0.860 U 0.42 0.43 -2.8 -0.430 0.670 Sexo (male) M 0.44 0.40 9.3 -234.30 1.120 0.260 U 0.04 0.03 6.7 1.030 0.300 Speaks an indigenous language M 0.04 0.02 10.0 -49.4 1.170 0.350 U 0.41 0.38 7.0 1.070 0.280 Has any work experience M 0.38 0.39 -2.9 58.70 -0.350 0.770 U 7.56 7.61 -5.4 -0.830 0.410 Offical grades (mean) M 7.58 7.56 2.0 63.90 0.230 0.790 Currently has student status U 0.7 0.73 -5.1 -0.770 0.440 only M 0.74 0.73 3.9 22.60 -0.480 0.740 Perception of School environment U 0.95 0.95 0.7 0.110 0.920 My school is unsafe M 0.95 0.94 6.6 -856.30 0.730 0.380 U 0.01 0.01 -1.6 -0.240 0.810 My school is dangerous M 0.01 0.01 0.0 100.00 0.000 1.000 Household Characteristics Lives with his/her mother and U 0.61 0.64 -4.9 -0.740 0.460 father M 0.65 0.61 9.5 -95.60 1.130 0.250 U 0.07 0.05 9.0 1.380 0.050 Lives with his/her father M 0.05 0.07 -1.5 83.00 -1.220 0.220 U 0.26 0.24 3.0 0.450 0.650 Lives with his/her mother M 0.24 0.27 -7.4 148.30 -0.870 0.380 U 0.36 0.32 9.2 1.410 0.160 Head of househols Sex M 0.33 0.37 -9.7 -5.40 -1.150 0.250 U 44.65 44.81 -1.9 -0.290 0.770 Head of household Age M 44.5 44.69 -1.8 9.20 -0.210 0.830 U 0.74 0.72 3.4 0.520 0.600 Pipied water M 0.75 0.72 6.4 -87.10 0.760 0.330 U 3.63 3.74 -6.0 -0.920 0.360 Room (mean) M 3.67 3.67 0.4 93.80 0.050 0.920 U 2.63 2.67 -3.4 -0.510 0.610 Bedrooms (mean) M 2.67 2.71 -3.4 -1.00 -0.380 0.700 U 0.8 0.89 -13.1 -2.000 0.050 Cell phone M 0.86 0.89 -3.7 74.80 0.400 0.600 Note: Kernel (0.001) </p><p>Sample Ps R2 LR chi2 P>chi2 MeanBias MedBias B R %Var Unmatched 0.023 30.22 0.025 6.2 5.1 36.1* 0.84 50 Matched 0.009 7.21 0.981 4.6 3.4 22.6 0.98 17 Supplementary material: True love: effectiveness of a school-based program to reduce partner violence among teenagers in Mexico City. Table S2. Description of dating violence at baseline and follow-up by exposure</p><p>Full sample Difference SCC, IL-1a SCC (SCC, IL-1 vs. SCC)a n 292 407 PANEL A: Dating violence- % of students Experienced Psychological Baseline 27.30 25.40 1.90 Follow-up 21.52 21.63 -0.11 Difference (Baseline vs. Follow-up)c -5.78 -3.77 Physical Baseline 9.71 12.90 -3.19 Follow-up 7.87 9.72 -1.85 Difference (Baseline vs. Follow-up)c -1.84 -3.18 Sexual Baseline 5.99 5.08 0.91 Follow-up 4.20 5.18 -0.98 Difference (Baseline vs. Follow-up)c -1.79 0.09 PANEL B: Dating violence- % of students</p><p>Perpetrated Psychological Baseline 38.20 33.42 4.78 Follow-up 30.53 29.16 1.37 Difference (Baseline vs. Follow-up)c -7.67 -4.26** Physical Baseline 13.11 17.38 -4.27 Follow-up 11.07 13.62 -2.55 Difference (Baseline vs. Follow-up)c -2.04 -3.76* Sexual Baseline 6.37 7.22 -0.85 Follow-up 4.96 5.18 -0.22 Difference (Baseline vs. Follow-up)c -1.41 -2.04* a Attended at least one session of True Love Curriculum could participate or could not participate as agents of change in enhancing the school climate through schoolyard activities. Kruskal-Wallis ANOVA Tests to identify signifiant differences. b Difference test between SCC, IL-1 and SCC **<0.01 *<0.05 c Difference test between baseline and follow-up **<0.01 *<0.05 Supplementary material: True love: effectiveness of a school-based program to reduce partner violence among teenagers in Mexico City. Table S3. Description of attitudes and beliefs toward violence at baseline and follow- up, by exposure</p><p>Full sample Differenc e (SCC, SCC, IL-1a SCC IL-1 vs. SCC)b n 381 504 PANEL A: Attitude and beliefs toward Mean of score violence (a) (range 1-4) Acceptance and justification of violence index (a) mean Baseline 1.27 1.29 -0.02 Follow-up 1.23 1.23 0.00 Difference (Baseline vs. Follow-up)c -0.04** -0.06* Acceptance of sexist attitudes index (a) mean Baseline 1.23 1.25 -0.02 Follow-up 1.28 1.32 -0.04 Difference (Baseline vs. Follow-up)c 0.05 0.07* Acceptance of sexist attitudes in dating index (a) mean Baseline 1.23 1.22 0.01 Follow-up 1.17 1.17 0.00 Difference (Baseline vs. Follow-up)c -0.06** -0.05* PANEL B: Participation in activities to % of students prevent dating violence Index (a) Baseline 24.40 24.95 -0.55 Follow-up 74.60 33.20 41.4** Difference (Baseline vs. Follow-up)c 50.2** 8.25* PANEL C: Knowledge of institutions which provide support to address dating % of students violence Index (a) Baseline 38.58 33.53 5.05 Follow-up 51.44 47.22 4.22* Difference (Baseline vs. Follow-up)c 12.86** 13.69** a Attended at least one session of True Love Curriculum could participate or could not participate as agents of change in enhancing the school climate through schoolyard activities. Kruskal-Wallis ANOVA Tests to identify significant differences (a) Index range: 1-4 b Difference test between SCC, IL-1 and SCC **<0.01 *<0.05 c Difference test between baseline and follow-up **<0.01 *<0.05 Supplementary material: True love: effectiveness of a school-based program to reduce partner violence among teenagers in Mexico City. Table S4. Intervention impact: Dating violence. Fixed-effects models. Subsample of students who both were exposed to the True Love curriculum and actively engaged in schoolyard activities</p><p>Full sample Female Male n 692 325 367 </p><p>Dating Violence SCC SCC SCC Coeff. Follow Relative Coeff. Follow- Relative Coeff. Follow- Relative [95%CI] -upa Effectb [95%CI] upa Effectb [95%CI] upa Effectb PANEL A: dating violence- experienced Psychological -0.05 0.22 -0.23 0.05 0.34 0.15 -0.19* 0.26 -0.73 [-0.36;-</p><p>[-0.15;0.06] [-0.09;0.18] 0.02] Physical 0.04 0.12 0.33 0.03 0.12 0.25 0.04 0.12 0.33 [-0.05 ;0.12] [-0.09;0.14] [-0.10;0.17] Sexual -0.03 0.05 -0.60 -0.03 0.07 -0.43 -0.04 0.04 -1.00 [-0.08;0.02] [-0.09;0.03] [-0.12;0.04] PANEL B: dating violence- perpetrated Psychological -0.05 0.29 -0.17 0.04 0.33 0.12 -0.18* 0.25 -0.72 [-0.34;-</p><p>[-0.15;0.06] [-0.09;0.17] 0.02] Physical 0.03 0.14 0.21 0.01 0.15 0.07 0.04 0.12 0.33 [-0.06;0.11] [-0.11;0.12] [-0.10;0.18] Sexual -0.02 0.05 -0.40 -0.03 0.05 -0.60 -0.01 0.06 -0.17 [-0.07;0.04] [-0.10;0.04] [-0.10;0.08] Impact is estimated by the coefficient of the interaction between the variables exposure (0=SCC 1=SCC, IL-2) and time (0=baseline 1=follow up). The models are adjusted by: age, official grades, first sexual intercourse, currently has boyfriend/girlfriend, has had sexual activity with current or the most recent partner, time in months of current or the most recent relationship, school group, mean of Rosenberg self-esteem scale, and cluster at school level * p<0.05 **p<0.01 a Prevalence among SCC group at follow-up b Effect size relative to SCC group at follow-up Supplementary material: True love: effectiveness of a school-based program to reduce partner violence among teenagers in Mexico City. Table S5. Intervention impact: Attitude and beliefs towards violence. Fixed-effects models. Subsample of students who both were exposed to True Love curriculum and actively engaged in schoolyard activities</p><p>Full sample Female Male n 817 361 456 Effec Effec Coeff. SCC Coeff. SCC Coeff. SCC Effect t t [95%CI] Follow- [95%CI] Follow- [95%CI] Follow- Sizeb up Meana Sizeb up Meana Sizeb up Meana</p><p>Acceptance and -0.03 1.23 -0.02 -0.03 1.15 -0.03 -0.03 1.29 -0.02 justification of violence index (a) [-0.08;0.03] [-0.09;0.04] [-0.13;0.06] Acceptance of sexist -0.02 1.32 -0.02 -0.05 1.26 -0.04 0.01 1.36 0.01 attitudes index (a) [-0.07;0.03] [-0.12;0.02] [-0.06;0.09] Acceptance of sexist -0.06* 1.17 -0.05 -0.06* 1.10 -0.05 -0.06 1.23 -0.05 attitudes in dating index [-0.15 - [-0.11;-0.00] [-0.10;-0.01] (a) 0.03]</p><p>Impact is estimated by the coefficient of the interaction between the variables exposure (0=SCC 1=SCC, IL-2) and time (0=baseline 1=follow up). The models are adjusted by: age, official grades, first sexual intercourse, currently has boyfriend/girlfriend, school group, mean of Rosenberg self-esteem scale, and cluster at school level * p<0.05 **p<0.001 (a) Score range: 1-4 a Mean index score among SCC group at follow-up b Effect size relative to SCC group at follow-up</p><p>Table S6. Program impact1: Participation in activities to prevent violence and knowledge of institutions that provide support to address violence. Fixed-effects models. Subsample of students who both were exposed to True Love curriculum and actively engaged in schoolyard activities</p><p>Full sample Female Male n 817 361 456 Non Non Non Exp Relativ Exp Relativ Exp</p><p>Coeff. Follow- e Coeff. Follow- e Coeff. Follow- Relative [95%CI] upa Effectb [95%CI] upa Effectb [95%CI] upa Effectb</p><p>Participation in activities 0.68** 0.33 2.06 0.68** 0.32 2.13 0.69** 0.34 2.03 to prevent dating violence. Index [0.60;0.76] [0.57;0.79] [0.57;0.80]</p><p>Knowledge of 0.12* 0.56 0.21 0.14* 0.64 0.22 0.12 0.51 0.29 institutions which [0.03;0.21] [0.02;0.27] [-0.01;0.25] provide support to address dating violence. Index Impact is estimated by the coefficient of the interaction between the variables exposure (0=SCC 1=SCC, IL-2) and time (0=baseline 1=follow up). The models are adjusted by: age, official grades, first sexual intercourse, currently has boyfriend/girlfriend, school group, mean of Rosenberg self-esteem scale, and cluster at school level * p<0.05 **p<0.001 a Percentage among SCC group at follow-up b Effect size relative to SCC group at follow-up Supplementary material: True love: effectiveness of a school-based program to reduce partner violence among teenagers in Mexico City.</p><p>Figure S1. Behavioral Theoretical Framework of the targeted risk factors in True Love Supplementary material: True love: effectiveness of a school-based program to reduce partner violence among teenagers in Mexico City.</p><p>Figure S2. Analytical Sample Supplementary material: True love: effectiveness of a school-based program to reduce partner violence among teenagers in Mexico City. Figure S3. Propensity Score Matching: graphical results Supplementary material: True love: effectiveness of a school-based program to reduce partner violence among teenagers in Mexico City.</p><p>Figure S4. Timeline of the intervention, evaluation and school calendar</p><p>2014 Feb Mar May June Aug Sep Nov Dec Intervention: School climate component Intervention: Schoolyard activities Summer Intervention: True Love Module 1+ Break Curriculum n=353 (92%)* Module 3+ n=342 (89%)* School Calendar 2nd semester of 10th grade 1st semester of 11th grade Evaluation measurements Follow- up survey +Each module included four 1-hour sessions. Sixteen 1-hour sessions in total * Attended at least one session of True Love Curriculum (paired sample) Note: In the True Love Curriculum the percentage of attendance to at least one session of each module was 92%, 91% and 89% for the first, second and third modules, respectively, attendance to the fourth module was much lower at 52% </p>