Externalities in the Classroom: How Children Exposed to Domestic Violence Affect Everyone’s Kids

Justin Wolfers
Many teachers believe that a “few bad apples” can spoil a whole classroom, reducing the learning of everyone in the room. While this is part of the folk wisdom of teaching, it has been surprisingly difficult to find these effects in the data.
But a very convincing new paper, by Scott Carrell of U.C. Davis and Mark Hoekstra of U.Pitt, “Externalities in the Classroom: How Children Exposed to Domestic Violence Affect Everyone’s Kids” (available here), suggests that these effects can be pretty big.
The real difficulty in this style of research is to find a useful proxy for whether or not a classroom is affected by a disruptive student. Previously researchers have used indicators like whether a student has low standardized test scores, but as any teacher knows, the under-performing kids may not be the disruptive ones. And if you analyze only a weak statistical proxy for classroom disruption, you get weak estimates, even when the true effects are large.
The truly innovative part of the Carrell and Hoekstra study begins with their search for potentially disruptive kids: they looked for those coming from particularly difficult family situations. In particular, they combed through court records and linked every domestic violence charge in Alachua County, Florida to the county schooling records of kids living in those households.
It’s a sad story: nearly 5 percent of the kids in their sample could be linked to a household with a reported domestic violence incident. (And given under-reporting, the true number may be much larger.)
The costs of this dysfunction are even more profound. Kids exposed to domestic violence definitely do have lower reading and math scores and greater disciplinary problems. But the effects of this dysfunction are not limited to the direct victims of this violence: kids exposed to kids exposed to domestic violence also have lower test scores and more disciplinary infractions.


Around 70 percent of the classes in their sample have at least one kid exposed to domestic violence. The authors compare the outcomes of that kid’s classmates with their counterparts in the same school and the same grade in a previous or subsequent year — when there were no kids exposed to family violence — finding large negative effects.
Adding even more credibility to their estimates, they show that when a kid shares a classroom with a victim of family violence, she or he will tend to under-perform relative to a sibling who attended the same school but whose classroom had fewer kids exposed to violence. These comparisons underline the fact that the authors are isolating the causal effects of being in a classroom with a potentially disruptive kid, and not some broader socio-economic pattern linking test scores and the amount of family violence in the community.
You likely already believe there is an equity rationale for trying to help those kids subject to difficult family situations. This research also suggests a compelling efficiency rationale, as the effects radiate well beyond the dysfunctional household.

2 thoughts on “Externalities in the Classroom: How Children Exposed to Domestic Violence Affect Everyone’s Kids”

  1. I am very surprised no one has found this worthy of comment. This is exactly what informed people around our elementary school (in particular) have been noticing for years. Here is a readable, detailed study that looks at the effects on classmates, of kids who are exposed to domestic violence. The authors even quote an initial research question to inspect that seems remarkably hands-on: “a nationally representative survey found that 85 percent of
    teachers and 73 percent of parents said that the ‘school experience of most students
    suffers at the expense of a few chronic offenders’ (Public Agenda, 2004)”
    Hello? These authors have found where those few chronic offenders come from, and where they come up with their ideas of what constitutes respect and how to treat others. This is an astonishingly applicable piece, and I sure hope more people involved with security and student behavior in the schools read it. Even back when I was in school, you avoided the bigger kids you knew were beat on at home, because you knew they would beat on you to get even with the world. And if their moms were beat on too, they tended to be sad, withdrawn and tired, or angry, unmotivated and sassy. Trust me, this did not depend on race for the most part either – mainly black, white and hispanic in the Twin Cities at the time. But as the Hmong families settled in more and took on more of the “American values” around them (by the mid-80s), then their children who witnessed domestic violence had the same sort of reactions. I know several people I am going to bring this paper to myself, if i must, to get them to truly read it.

  2. I agree with you Millie. You ask why this article has not received more comments. I don’t know, but I find that it is something people don’t want to discuss. Too unPC to even discuss. I am overwhelmed by the amount of denial there is on the part of Madison citizens. I see places like some parts of Chicago being much more upfront about the problems. We can’t deal with the problems if we refuse to recognize or talk about them openly.

Comments are closed.