Table S1. Propensity Score Matching: Bias Correction
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
U=unmatched / Mean / % reduct. |bias| / t-testVariable / M=matched / SCC, IL-1 / SCC / %Bias / t / p>|t|
Individual Characteristics
Age (mean) / U / 15.99 / 16.28 / -23.0 / -3.490 / 0.000
M / 16.032 / 16.04 / -0.3 / 9.88 / -0.040 / 0.860
Sexo (male) / U / 0.42 / 0.43 / -2.8 / -0.430 / 0.670
M / 0.44 / 0.40 / 9.3 / -234.30 / 1.120 / 0.260
Speaks an indigenous language / U / 0.04 / 0.03 / 6.7 / 1.030 / 0.300
M / 0.04 / 0.02 / 10.0 / -49.4 / 1.170 / 0.350
Has any work experience / U / 0.41 / 0.38 / 7.0 / 1.070 / 0.280
M / 0.38 / 0.39 / -2.9 / 58.70 / -0.350 / 0.770
Offical grades (mean) / U / 7.56 / 7.61 / -5.4 / -0.830 / 0.410
M / 7.58 / 7.56 / 2.0 / 63.90 / 0.230 / 0.790
Currently has student status only / U / 0.7 / 0.73 / -5.1 / -0.770 / 0.440
M / 0.74 / 0.73 / 3.9 / 22.60 / -0.480 / 0.740
Perception of School environment
My school is unsafe / U / 0.95 / 0.95 / 0.7 / 0.110 / 0.920
M / 0.95 / 0.94 / 6.6 / -856.30 / 0.730 / 0.380
My school is dangerous / U / 0.01 / 0.01 / -1.6 / -0.240 / 0.810
M / 0.01 / 0.01 / 0.0 / 100.00 / 0.000 / 1.000
Household Characteristics
Lives with his/her mother and father / U / 0.61 / 0.64 / -4.9 / -0.740 / 0.460
M / 0.65 / 0.61 / 9.5 / -95.60 / 1.130 / 0.250
Lives with his/her father / U / 0.07 / 0.05 / 9.0 / 1.380 / 0.050
M / 0.05 / 0.07 / -1.5 / 83.00 / -1.220 / 0.220
Lives with his/her mother / U / 0.26 / 0.24 / 3.0 / 0.450 / 0.650
M / 0.24 / 0.27 / -7.4 / 148.30 / -0.870 / 0.380
Head of househols Sex / U / 0.36 / 0.32 / 9.2 / 1.410 / 0.160
M / 0.33 / 0.37 / -9.7 / -5.40 / -1.150 / 0.250
Head of household Age / U / 44.65 / 44.81 / -1.9 / -0.290 / 0.770
M / 44.5 / 44.69 / -1.8 / 9.20 / -0.210 / 0.830
Pipied water / U / 0.74 / 0.72 / 3.4 / 0.520 / 0.600
M / 0.75 / 0.72 / 6.4 / -87.10 / 0.760 / 0.330
Room (mean) / U / 3.63 / 3.74 / -6.0 / -0.920 / 0.360
M / 3.67 / 3.67 / 0.4 / 93.80 / 0.050 / 0.920
Bedrooms (mean) / U / 2.63 / 2.67 / -3.4 / -0.510 / 0.610
M / 2.67 / 2.71 / -3.4 / -1.00 / -0.380 / 0.700
Cell phone / U / 0.8 / 0.89 / -13.1 / -2.000 / 0.050
M / 0.86 / 0.89 / -3.7 / 74.80 / 0.400 / 0.600
Note: Kernel (0.001)
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
Table S2. Description of dating violence at baseline and follow-upby exposure
Full sampleSCC, IL-1a / SCC / Difference (SCC, IL-1 vs. SCC)a
n / 292 / 407
PANEL A: Dating violence-Experienced / % of students
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-Perpetrated / % of students
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*
aAttended 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
cDifference test between baseline and follow-up **<0.01 *<0.05
Table S3. Description of attitudes and beliefs toward violence at baseline and follow-up, by exposure
Full sampleSCC, IL-1a / SCC / Difference (SCC, IL-1 vs. SCC)b
n / 381 / 504
PANEL A: Attitude and beliefs toward violence (a) / Mean of score
(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 prevent dating violence Index (a) / % ofstudents
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 violence Index (a) / % ofstudents
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**
aAttended 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-1and SCC **<0.01 *<0.05
c Difference test between baseline and follow-up **<0.01 *<0.05
Table S4. Intervention impact: Dating violence. Fixed-effects models. Subsample of students who bothwereexposedtotheTrue Love curriculum andactivelyengaged inschoolyard activities
Full sample / Female / Malen / 692 / 325 / 367
Dating Violence / Coeff. [95%CI] / SCC Follow-upa / Relative Effectb / Coeff. [95%CI] / SCC Follow-upa / Relative Effectb / Coeff. [95%CI] / SCC Follow-upa / Relative 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
[-0.15;0.06] / [-0.09;0.18] / [-0.36;-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
[-0.15;0.06] / [-0.09;0.17] / [-0.34;-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
Table S5. Intervention impact: Attitude and beliefs towards violence. Fixed-effects models. Subsample of studentswhobothwereexposedtoTrue Lovecurriculum and activelyengaged in schoolyardactivities
Full sample / Female / Malen / 817 / 361 / 456
Coeff. [95%CI] / SCC Follow-up Meana / Effect Sizeb / Coeff. [95%CI] / SCC Follow-up Meana / Effect Sizeb / Coeff. [95%CI] / SCC Follow-up Meana / Effect Sizeb
Acceptance and justification of violence index (a) / -0.03 / 1.23 / -0.02 / -0.03 / 1.15 / -0.03 / -0.03 / 1.29 / -0.02
[-0.08;0.03] / [-0.09;0.04] / [-0.13;0.06]
Acceptance of sexist attitudes index (a) / -0.02 / 1.32 / -0.02 / -0.05 / 1.26 / -0.04 / 0.01 / 1.36 / 0.01
[-0.07;0.03] / [-0.12;0.02] / [-0.06;0.09]
Acceptance of sexist attitudes in dating index (a) / -0.06* / 1.17 / -0.05 / -0.06* / 1.10 / -0.05 / -0.06 / 1.23 / -0.05
[-0.11;-0.00] / [-0.10;-0.01] / [-0.15 - 0.03]
Impact is estimated by the coefficient of the interaction between the variables exposure (0=SCC1=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
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 studentswhobothwereexposedtoTrue Lovecurriculum and activelyengaged in schoolyardactivities
Full sample / Female / Malen / 817 / 361 / 456
Coeff. [95%CI] / Non Exp Follow-upa / Relative Effectb / Coeff. [95%CI] / Non Exp Follow-upa / Relative Effectb / Coeff. [95%CI] / Non Exp Follow-upa / Relative Effectb
Participation in activities to prevent dating violence. Index / 0.68** / 0.33 / 2.06 / 0.68** / 0.32 / 2.13 / 0.69** / 0.34 / 2.03
[0.60;0.76] / [0.57;0.79] / [0.57;0.80]
Knowledge of institutions which provide support to address dating violence. Index / 0.12* / 0.56 / 0.21 / 0.14* / 0.64 / 0.22 / 0.12 / 0.51 / 0.29
[0.03;0.21] / [0.02;0.27] / [-0.01;0.25]
Impact is estimated by the coefficient of the interaction between the variables exposure (0=SCC1=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
bEffect 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.
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.
Figure S2. Analytical Sample
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.
Figure S4. Timeline of the intervention, evaluation and school calendar
2014Jan / Feb / Mar / Apr / May / June / July / Aug / Sep / Oct / Nov / Dec
Intervention: School climate component
Intervention: Schoolyard activities / Summer Break
Intervention: True Love Curriculum / Module 1+ n=353 (92%)* / Module 2+ n=345 (91%)* / Module 3+ n=342 (89%)* / Module 4+ n=201 (52%)*
School Calendar / 2nd semester of 10th grade / 1st semester of 11th grade
Evaluation measurements
Baseline survey / 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%