There are limitations of using cross-sectional data to describe changes over time. Time trends obtained from cross-sectional data have a different meaning than time trends obtained from cohort data. Cohort studies follow up an initial study population over time, and therefore the time trends refer to changes in the individuals over time, and are best suited for risk analysis. Cross-sectional studies use a new representative sample of the population each time, so the time trends refer to changes in the population over time, and are appropriate for burden analysis. A surveillance system seeks information on the same issues over an extended period of time. Therefore, data can be useful for determining adequate strategies and prevention, as is the case in this article, that presents data from a surveillance system.
In the past, to face violence in schools by removing students suspected of committing violent acts and asking the judiciary system to take the punitive leadership has been an unsuccessful policy to stop and/or decrease school violence . Most recently, a holistic approach to school violence looks promising because not only does it include the criminal act committed by minors, it also takes into account the cultural, social, economic and environmental factors that promote violence [18, 19]. The superiority of the holistic approach has been shown by comparing different typologies of school-based violence prevention strategies. Interventions that use psychosocial and psycho-educational programs or multiple strategies with key stakeholder groups working to reduce aggression reveal strong evidence for prevention. Conversely, the use of standard strategies for the entire school or school district such as security apparatus and policies, peer-led programs, discipline policies and rules, threat assessment and crisis response have shown poor or minimal evidence of violence prevention most of the time . More recently, those programs that link the interests of families and teachers to build social skills among students from earlier grades (≥ 5th) and target multilevel approaches to high risk populations with abundance of violence among adolescents have resulted in a substantial reduction of school dropout, fewer delinquency reports, fewer arrests by age 19, and increasing social skills among adolescents . Other validated violence prevention programs are listed at the end of this article.
To accomplish a holistic, preventative, school-based approach against violence, it is necessary to understand the epidemiological profile of violence in the school based on comparative evidence as provided by the GSHS [1–3, 22]. Data from the first GSHS is currently available for some Latin American countries, a region where school violence among youth is escalating [23–30].
Absenteeism is an unspecific but useful proxy indicator of violence in schools used in many studies [31–37]. However, in the Americas, only a handful of countries allow access to official data on school absenteeism. The GSHS-Lara shows that absenteeism is a growing problem. The prevalence of students who avoid going to school due to feeling unsafe at their school or on their way to or from school doubled from 1 in 9 students (2004) to 1 in 5 students (2008), figures being higher for males (13.1% 2004 vs. 25.2% 2008) than for females (8.8% 2004 vs. 16.7% 2008). This makes GSHS-Lara 2008 the third highest prevalence after the 28.4% of GSHS-Santiago, metropolitan area 2005 (Chile) and 21.25% of GSHS-Quito 2007 (Ecuador).
Being robbed inside and outside of school can be a contributor to absenteeism among students because it produces feelings of futility, inadequacy, and loss in the victim . In the GSHS-Lara, students were robbed more frequently inside the school than outside of the school: 21.7% (2004) and 22% (2008) in the school, and 14.2% (2004) and 14.8% (2008) elsewhere, respectively.
Bullying, physical fighting, and carrying a weapon are important indicators of youth violence, which not only contribute to student absenteeism but can also lead to more severe forms of violence . GSHS-Lara showed that the P% of students who suffered from bullying increased for both genders, i.e. in males from 35.6% (2004) to 46.2% (2008) and in females from 31.4% (2004) to 41.1% (2008); figures close to 1 in 2, which is comparable with the GSHS-Santiago, Metropolitan Area 2005 (Chile); followed by the USA and GSHS-Bogotá 2007 (Colombia), close to 1 in 3; with the third spot for the GSHS Argentina-2007 and GSHS-Quito 2007 (Ecuador), close to 1 in 4 [25–27, 30, 39].
Bullying is often considered an inevitable part of growing up, a kind of "small and subtle violence" if compared with those cases of "high violence" associated with crime . Currently bullying is known to be one of the most prevalent dire experiences that students have to endure at school, as it is associated with physical aggression, verbal harassment, and psychological manipulation leading to difficulty in internalizing moral values, escalating anger, school absenteeism, poor academic performance, mood disorders, humiliation, abuse of substances and eating disorders, to name but a few . The GSHS-Lara showed that at least 1 in 7 male students was a victim of bullying associated with physical attacks (18.5% in 2004 vs. 14.3% in 2008) and unfortunately, there is an increasing prevalence for females (8.3% in 2004 vs. 11.0% in 2008), as you can see in Table 1.
Physical fighting is very common among school-age children in many parts of the world . The GSHS-Lara 2008 showed that 28.2% of males and 15.2% of females had been physically attacked. These data place Venezuela in third place compared with GSHS reports from other Latin American countries such as Argentina and Chile [26–28, 30]. The prevalence of active participation in physical fighting is high and remains unchanged over time: males 44.9% (2004) vs. 43.1% (2008) and females 12.0% (2004) vs. 14.7% (2008). These results are consistent with international reports indicating that one-third of the male students have been involved in fighting . Compared with other Latino countries, Venezuela is in third place after Chile (close to 1 in 2) and the rest of GSHS in Latin American such as Argentina, Colombia and Ecuador (close to 1 in 3) [25, 26, 29, 30]. Data from GSHS-Lara show that the number of students carrying a weapon increased for both genders to 1 in 9 males and 1 in 28 females in 2008, figures that are close to those reported in Cape Town, South Africa for males (1 in 10); but below those reported for the USA (1 in 4 males and 1 in 15 females in 9th to 12th grade) and the Netherlands (1 in 8 for both sexes) and Scotland (1 in 3, also for both sexes) . The GSHS-Lara did not explore where weapons had been obtained; other surveys showed that youth often have access to guns at home, where it is common for parents to have positive perceptions of their children's understanding and behavior towards guns, i.e. 75% of parents thought their children [ages 4 to 12 years] could tell the difference between a toy gun and a real gun, and 53% said they could trust their children not to touch loaded guns. However, the reality indicates that the possession of a gun may facilitate a homicide when adolescents are involved in physical conflicts [1–3]. Finally, despite the profile of violence shown by the GSHS-Lara, students did not report any improvement in exposure to violence prevention lectures at school.