As more and more children grow up in single-parent families, it’s a challenge making sure non-custodial parents, usually fathers, pay child support. Federal rules impose stiff penalties on working parents who don’t pay. In many cases, however, this tough approach seems to be failing. New research shows that a high burden of child support arrears actually discourages fathers from working, says Daniel Miller, a professor at Boston University.

“Back child support can spell disaster for dads,” says Miller, whose article, “Falling Further Behind? Child Support Arrears and Fathers’ Labor Force Participation,” appeared in the December 2012 Social Service Review and won the Frank R. Bruel Memorial Prize for best article in the journal in 2012.

The total amount of unpaid child support in 2010 stood at $110 billion, and 11.3 million child support cases were in arrears in 2011. Most of the money is owed by a disproportionately small number of fathers. One study of nine states showed that 10 percent of fathers owed more than half the total. These are often men of color who have been hurt hardest by the recent recession.

Miller and his co-author, Ronald Mincy, a professor at Columbia University, studied data from the Fragile Families Wellbeing Study, a longitudinal study that follows families over many years, to determine how child support arrears affect participation in the workforce. The study showed that fathers work an average of two to three fewer weeks a year if they owe back child support.

But this effect seemed to depend on how much they owed relative to their incomes. Fathers who were marginally attached to the workforce—i.e., didn't have steady, full-time work—actually worked more weeks a year when they had only a small arrears burden.

One question the authors wanted to answer was whether working less and owing back child support were simply the consequences of a poor work ethic. They concluded that this was not the case because even fathers with steady, full-time jobs who owed back child support worked less than their counterparts who didn’t owe child support.

The study has clear policy implications. It shows that existing child support policy draws fathers who owe small amounts of back child support and are marginal workers into more regular work. At the same time it seems to discourage poor fathers from working when they are burdened with high arrears and have little or no recent employment. This of course deprives their children of needed support.

Another implication concerns a proposal, long bandied about, to extend the Earned Income Tax Credit to non-custodial parents, who currently are eligible for a much smaller credit. As envisioned, though, this extension would exclude fathers who owe back child support, thus further punishing a disadvantaged group for whom existing penalties already do not work. Another alternative that seems to work is a Wisconsin program that offers fathers debt forgiveness in exchange for making regular payments.

“We’re holding dads to their obligations,” Miller says. “It’s hard to argue with that. But this suggests there are some hidden costs.”