When the homicide rate increases in a community, primary school children are more likely to fail a grade.

A new study, co-authored by NYU sociology professor Florencia Torche and doctoral student Monica Caudillo, found these results. The study is based on the statistical analysis of a large data set that merged information about every school in Mexico across 21 years between 1990 and 2010.

While it is difficult to measure the effects of violence on developing minds, Torche and Caudillo used various statistical techniques to understand the effects of local violence on children.

“The statistical techniques we use allow us to capture a causal effect of violence on grade failure, and not simply a correlation,” Torche said.

Torche said it is more common for poor children to live in violent communities, and the impact on their school performance is likely to contribute to the intergenerational reproduction of poverty.

“Research in the [United States] usually focuses on the effect of local violence on adolescents,” Torche said. “Our study demonstrates that exposure to local violence affects children since they are very young.”

Mark Alter, a professor of educational psychology, said students have always been affected academically, socially and psychologically by out-of-school factors — the most powerful of which is community.

“Students who experience poverty and all the problems that come with it have enough trouble just surviving, much less succeeding in school,” Alter said.

To address these out-of-school factors that affect school performance, Alter said the focus should be on raising revenues to fund after-school programs, basic health programs, social work and other services at low-income schools.

Torche said more research should be done on the negative psychological impacts of violence on children.

“This negative effect emerges because violence induces fear, anxiety and stress among children, and that affects their school performance,” Torche said. “More research is necessary to fully understand these and other mechanisms.”

Caudillo said in a press release to the American Sociological Association that the research could indicate a need for school programs to help children cope with violence.

“Our research suggests that in violent environments it may be important to consider initiatives such as teacher training and school programs designed to help children manage and reduce the symptoms associated with exposure to violence in order to alleviate their negative impact,” Caudillo said.

A version of this article appeared in the Tuesday, April 22 print edition. Marita Vlachou is a staff writer. Email her at [email protected].