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.
and 
. You can also watch it on 
So if we can just solve domestic violence….
Kudos to Carrell and Hoekstra for their creativity and insight in identifiying and quantifying a potentially useful metric to measure a (believed to be) root cause of classroom disruptions.
My mother has taught special needs and abused children for over thirty years both as part of CPS and as a reading specialist. She would certainly question Mr. Dokes’ dismissive word choice, but agree with his sentiment: A teacher’s influence on a disruptive student is quite limited if the student lives in a toxic home environment, and even a higly skilled teacher can be easily overwhelmed with a small number of disruptive students.
This sort of research could help to shift the focus more toward what the root causes of disruptive children are rather than what teachers ought to be doing to mitigate that disruption, but based on the posts thus far, I am not hopeful.
@ concerned parent
There’s reaching out to help a troubled student, and there’s holding back the whole class due to the minority of students in the classroom that is formed by these troubled students. If only we had as many parents concerned about the lack of reaching out towards the gifted students as we do towards the troubled ones.
Joe Dokes and Rachel both make very good points.
I think the takeaway from this post is that kids who are mistreated at home become difficult to handle in a classroom environment. This is largely conjecture, but I’d say a kid who is abused is going to have a hard time subjecting himself to the authority of a teacher in the appropriate ways. What lessons has he learned from home?
This is a tragic state of affairs. Only a trained professional can control this child in a classroom, and somehow turn it into a positive experience for the class and even the child involved. In my experience as a NYC 8th grade teacher, showing the child that you care about them and actually want to help them goes a long way, but it isn’t enough. You also need to address the simple fact that some kids may actually be TRYING to make your job harder. This is what was especially hard for me to swallow and to correct.
Those of you who are quick to criticize Joe need to understand how powerless a teacher feels when his “bag of tricks” is empty and he simply can’t stop a few students from ruining the experience for everyone else. How painful it is to look into the eyes of a student, desperate to succeed, begging you to stop the madness – while another child delights in seeing the very pain on your face! Joe is not criticizing the study, except to say “tell me something I didn’t know!” To a 15 year teacher, this study is tantamount to a study showing a link between fall-related injuries and gravity.
But I agree with Rachel’s point also. Teachers need to be treated like trained professionals. All the rules to which teachers are subject are designed to protect the kids, but I believe they hamstring the teachers’ efforts to protect the kids from each other. These externalities are what the teachers (or the schools) should be given the authority to prevent. Not well-trained myself, I never found something within my authority that could be done to stop things when they got bad.
The police certainly can’t fire their guns unless the circumstances are dire and necessary. But they are highly trained when and how they should do so, if necessary. Teachers, by this analogy, are not given the right metaphorical weapons, nor trained how to use them even if they were. But higher expectations and salaries aren’t going to do it, you still have to arm the teachers with measures they can take. And frankly, these measures may come out sounding extreme to lay people, but in the hands of the truly trained professionals that teachers should be, they could be life-savers.
There is no doubt, domestic violence is one of the major reasons that affect a child negatively. It is really has everything to do with the family situation. I am not saying that a child from a peaceful family life can not be disruptive, but the thing is that that is of an exception. Moreover, I also think that violence in the video games and television programs can also affect a child negatively. When a child kill someone by his pistol in a video game, then it is very usual that he/ she will fantasize it, imagining he/ she is always doing the same thing in his/ her real life. Children should not be given these kind of destructive video games, rather they should be given easy to use and puzzling games that would also help them grow their intellect.
Also, teachers play a very important role in the lives of children who are being abused and neglected through the exposure of domestic violence. In many case it is the teacher or another school staff who the child reaches out to directly or indirectly concerning their home life. As a child protection social worker, I know that many of the reports of abuse and neglect come from school staff. Looking back at my years in the classroom, there many not have been any direct reports to me from a child, but I can see now how many of the kids I worked with were reaching out to me for help and most the time I just saw it has bad behavior and not a indicator of something awful happening within their home.
@Michael F. Martin (and Bob Jones)
Convexity is not a requirement for rooms. One could just design classrooms to be simple but non-convex polygons (e.g. a many-pointed star) and stick the jerks in the corners of the outer vertices.
In fact, you might even be able to tessalate them for minimal construction costs of multiple classrooms…
@Joe Dokes
Both of my parents were educators (my dad for 30+ years and my mom for 10+ years), and I know they (and most experienced teachers) can relate to your four jerks rule.
My guess is that ‘concerned parent’ and ‘Rachael’ simply don’t have much experience educating other people’s children.
At the same time, I’m not sure it’s productive to belittle the researchers that gave us this study. I don’t think they spent 15 years writing the paper so their approach might have been a bit more efficient.
Finally Joe, since you read this blog, I know you are more intellectually curious than most people. Thanks for spending your time passing that on to your students.