As our children head back to school again, it is useful to ask why so many are doing so poorly. It seems we've tried everything to improve standardized test scores among disadvantaged students, with little success.

But perhaps the answer partially lies in the home, not in the school. It turns out that children raised by single parents account for 71 percent of high school dropouts, according to federal statistics, and that children who have shared parenting after their parents separate due to divorce do considerably better.

Shared parenting is a flexible arrangement in which children spend as close to equal time as possible with each parent after separation or divorce – if both parents are fit and there has been no domestic violence. This stands in sharp contrast to the outdated traditions of most family courts, which assign sole physical custody to one parent, usually the mother, and just a small amount of "visitation" to the other parent.

Consider the wealth of data that shows as much.

As far back as 1977, a study by the National Center for Education Statistics entitled "Fathers' Involvement in Their Children's Schools" concluded that, "There is also evidence that the involvement of nonresident fathers increases the likelihood that children in grades 6 through 12 get mostly A's and that they enjoy school..."

Linda Nielsen, a professor of educational and adolescent psychology at Wake Forest University, recently published research titled, "Divorced Fathers and Their Daughters: A Review of Recent Research." She found that children, specifically daughters, need a relationship with their father post-divorce. Pantene and Mattel used her research to create 30-second Super Bowl spots in 2016 and 2017, respectively, showing dads playing with their daughters. Her research concluded that daughters who have actively involved fathers tend to have more self-confidence, better mental health, and are more successful in school.

The Office for National Statistics (in the U.K.) report shows a father's level of education is the strongest factor in determining a child's future success at school, while a mother's education level was important to a lesser degree.

A 2014 review of nearly 50 peer-reviewed research papers on post-divorce parenting found that almost every study demonstrated better results for children who had shared parenting after parental separation or divorce; the improved outcomes were reflected in many measures, including education. The results were endorsed by 110 experts around the world.

Yet, our family courts are ignoring these statistics. It's striking that our family courts, according to the Census Bureau, award mothers sole physical custody more than 80 percent of the time. The other parent, usually the father, is seldom awarded enough parenting time to have a positive influence during the school week.

These findings should be a cause for optimism. It appears that a simple change in family law, one that would reflect today's overlapping gender roles in parenting, will have a positive effect on education, and this improvement would cost taxpayers nothing. Improvements would be seen within two or three years. In this year alone, 25 states have considered legislation seeking to turn shared parenting from the exception to the norm. At least two states, Kentucky and Missouri, have passed new laws within the past year encouraging shared parenting, while others, such as Massachusetts and Florida, have come close to passing such laws.

Plus, shared parenting has been the status quo outside the U.S in places including Sweden and Australia for years. Research presented at this spring's International Conference on Shared Parenting in Boston, sponsored by National Parents Organization, overwhelmingly supported the two-parent model.

Over the past few decades, per-pupil K-12 spending has increased two- to three-fold in many cities. We have tried smaller classes, teacher-run schools, charter schools, vouchers for private schools, early childhood education, special education, compensatory education, multicultural education, and many, many more reforms. And we have nearly tripled the number of teachers while the number of pupils has increased only 50 percent. While many of these programs have had positive results in small studies, it has not been possible to scale them up to deal with the millions of disadvantaged children, so overall results have barely budged.

Shared parenting is a simple change that could make a difference at no cost. Our children's futures are at stake. If we don't want them to fall behind those whose parents are together, legislators and judges must act to change laws to make shared parenting the norm.

Ned Holstein, MD, is founder and chair of the board of the National Parents Organization. He was appointed by the governor of Massachusetts to the Massachusetts Working Group on Child-Centered Family Law, and he was previously appointed by a Massachusetts chief justice to a task force charged with reviewing and revising the state's child support guidelines.

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