Children who enter kindergarten after experiencing repeated household changes are more likely to display problem behaviors that inhibit learning and disrupt classrooms, Paula Fomby of the University of Michigan and Stefanie Mollborn of the University of Colorado show. Such changes include residential moves and shifts in family composition and household routines.

Their findings—coupled with other recent research on school readiness—can help policymakers and program directors better identify children most at risk for behavior problems and target interventions, such as high-quality subsidized preschool programs.

Researchers are focusing on kindergarten behavior because the early school years set the stage for a child’s entire school career, Mollborn explains. “There’s a correlation between achievement in kindergarten and first grade and academics at the end of high school.”

Some Achievement Gap Disparities Solidify Before Kindergarten

Closing achievement gaps between advantaged and disadvantaged students is a priority for policymakers, but by the time children arrive in kindergarten some of the disparities have already solidified, Mollborn points out.

Fomby and Mollborn examined the “constellation of disruptive events” that a child must adapt to during their preschool years, distinguishing normal levels of change from instability that threatens healthy development.1

They used data from the Early Childhood Longitudinal Study, Birth Cohort (ECLS-B), a nationally representative sample of 4,750 U.S. children born in 2001 and followed from infancy through the start of kindergarten. Their analysis examined residential moves and changes in child care arrangements, parents’ work hours, and household composition (such as parents splitting up, and other adults or new siblings entering the household).

They compared each child’s exposure to household change with levels of teacher-reported behavior problems, such as aggression, rule breaking, temper outbursts, and inability to share or focus.

High Levels of Change Put Children’s Development at Risk

On average, children experience seven changes before entering school, with nearly all children experiencing some type of change. Changes in child care settings, household moves, and maternal employment shifts are most common.

Fomby and Mollborn find that teachers tend to identify more problem behaviors in children who experienced higher than average levels of change, chronic change, and change in several areas concurrently, even after taking family characteristics into account.

“Children need stability, but we know that they can deal with some amount of change,” explains Mollborn. “It’s change at a level that shakes the family system multiple times that seems to put their development at risk.”

By focusing not only on whether both parents are present in the home but also on other key settings where children experience change, Fomby says, their approach offers teachers and school administrators a more comprehensive view of family instability. Many children “carry a history of disruption into the classroom,” she points out.

Their findings also underscore the role stress plays in a child’s development, showing that adapting to change is more challenging for children when it is frequent, persistent, and above normal levels.

Family Composition Changes May Negatively Affect All Children in a Household

Stress and family instability may also help explain why children being raised with half-siblings or stepsiblings are more likely to behave aggressively in kindergarten than their similar peers raised with only full siblings.2 For this related study, based on a subset of ECLS-B data, Fomby and Mollborn teamed up with Joshua Goode of the University of Colorado.

They suggest that when at least one child in the household has a biological parent living elsewhere, the behavior of all children in the household may be negatively affected. Their analysis shows that children raised with half-siblings or stepsiblings, on average, have more behavior problems in all family types studied—those living with both biological parents, a single parent, or their mother and a stepfather or cohabiting partner. (One in six U.S. children is being raised in a household with stepsiblings or half-siblings.)

Prior work has shown that having an absent parent, and particularly an absent father, is associated with a higher risk of aggressive behavior in younger children, Fomby reports. “Children live in a family system,” she explains. “If one child experiences a disruptive event, other children in the family may absorb the effects—they likely influence each other.”

Repeated Household Moves Take a Toll on Behavior

In another study, Mollborn and colleagues used the ECLS-B data to look more closely at the connection between household moves and problem behaviors.Children who experienced three or more moves before they entered school or whose households relocated to a more socioeconomically disadvantaged neighborhood tend to have higher problem behavior scores from teachers, she shows.

No matter what the family income level, the researchers find that frequent residential moves have a similar impact on kindergarteners’ behavior scores. “Parents’ income and education do not appear to buffer the impact of moving on children,” she notes.

About 71 percent of children moved before starting kindergarten, but only 14 percent moved four or more times. While the data do not distinguish between wanted moves and unwanted moves (such as moving closer to family versus an eviction), repeated moves likely signal instability, she says.

In Mollborn’s view, housing policies that promote stability while encouraging upward mobility for those who desire it appears a promising intervention. She also suggests that early childhood educators could target frequent movers with extra support, but notes these children are least likely to stay in the same place long enough to benefit.

Interrelated Factors Influence Which Children Face the Highest Risks

To better identify the children most likely to struggle when they enter school, Mollborn broadened her analysis of ECLS-B data, examining family resources and health risks along with family instability.4 She looked for interrelated factors that tend to cluster, dividing children into four statistically similar groups. The analysis included more than 40 measures, such as household income, food insecurity, medical insurance, special-needs household members, diet quality, sleep patterns, secondhand smoke, and exposure to violence. In addition to behavior problems in kindergarten, Mollborn examined the relationship of these measures to child health and school achievement.

She finds that the most vulnerable group of children—those who experience high levels of instability—also tend to “live in or near poverty with single mothers whose educational attainment is low and assets are few.” Food insecurity, special-needs household members, and exposure to violence and secondhand smoke are common.

Mollborn identified another group of children who live with single mothers and experience high levels of instability, but this group faces somewhat lower risks of health, behavior, and educational problems. These children tend to live in extended-family households, have higher household incomes, attend a daycare center, and have mothers who work outside the home.

“Narrow policies aimed at reducing single motherhood miss the diversity of environments children experience,” she says.

Interventions Can Mitigate the Impact of Household Disruptions

This analysis provides support for interventions that modify environments rather than focusing on single factors, Mollborn argues. “Beyond preschool, Head Start has wraparound offerings for parents, such as health care and employment services,” she says. “Home nurse visitation programs for young mothers address multiple concerns in early life. And child care subsidies simultaneously address children’s early educational needs and mothers’ employment needs.”

For children who have experienced a lot of disruption, policies that “shore up stability in other dimensions of their lives” are crucial, Fomby argues. For example, ensuring the child can remain in the same classroom following a household move may lessen stress and contribute to better behavior.

Mollborn is not surprised that birth to age five is a vulnerable time for children. “One-fifth of U.S. children under age five live in poverty. Child care costs are as high as college tuition, but there’s no equivalent to financial aid to pay for them. Many families are financially strapped.”

This article was produced under a grant from the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD). The work of researchers from the following NICHD-funded population research centers was highlighted in this article: University of Colorado, Boulder, and University of Michigan.



  1. Paula Fomby and Stefanie Mollborn, “Ecological Instability and Children’s Classroom Behavior in Kindergarten,” Demography 54, no. 5 (2017): 1627-51.
  2. Paula Fomby, Joshua A. Goode, and Stefanie Mollborn, “Family Complexity, Siblings, and Children’s Aggressive Behavior at School Entry,” Demography 53, no. 1 (2016): 1-26.
  3. Stefanie Mollborn, Elizabeth Lawrence, and Elisabeth Dowling Root. “Residential Mobility across Early Childhood and Children’s Kindergarten Behavior,” Demography 55 (2018): DOI 10.1007/s13524-018-0652-0.
  4. Stefanie Mollborn, “Young Children’s Developmental Ecologies and Kindergarten Readiness,” Demography 53, no. 6 (2016): 1853-82.