The federal government has made marriage promotion among single mothers a key part of its continuing effort to fight poverty.

But that approach has missed the mark because marriage doesn't provide the same benefits to poor, single mothers as it does for others, according to Kristi Williams, associate professor of sociology at The Ohio State University.

"If the goal of marriage promotion efforts was truly to lower poverty rates and improve the well-being of unmarried parents and their children, then it is time to take a different approach," Williams said.

That could include preventing unwanted births and giving more child care support for single mothers, she said.

Williams wrote a briefing paper on the issue (Promoting Marriage among Single Mothers: An Ineffective Weapon in the War on Poverty?) for The Council on Contemporary Families. Her report was one of two released today by the CCF to assess the state of the War on Poverty on its 50th anniversary.

It's easy to see why marriage promotion is appealing, Williams said: About 46 percent of children in single-mother households were living in poverty in 2013, compared to 11 percent of children living with two married parents.

Marriage promotion became an official U.S. policy in 1996 when Congress passed welfare reform legislation that allowed states to spend welfare funds on a range of efforts to get single mothers to marry. It has continued, with some modifications, to this day.

"But the flaw in this approach is the assumption that all marriages are equally beneficial," Williams said.

In fact, research shows that single mothers living in impoverished neighborhoods are likely to marry men who won't help them get out of poverty. These men are likely to have children from other partnerships, lack a high school diploma, and have been incarcerated or have substance abuse problems, Williams noted.

Those who do marry usually don't stay that way. One study found that nearly two-thirds of single mothers who married were divorced by the time they reached 44 years old.

"Single mothers who marry and later divorce are worse off economically than single mothers who never marry," she said.

Promoting marriage among single mothers may not help their children, either. Recent research by Williams and several colleagues found no physical or psychological advantages for the majority of teenagers born to a single mother who later married.

Rather than promoting marriage, the government should focus on preventing unintended births, Williams said. She found in one study that having a child outside of marriage is associated with negative mental health outcomes among African American women only when the birth was unexpected.

"Persuading low-income women to delay childbirth or get married requires changing behaviors that are in many ways rational given their limited opportunities. And there is no evidence that doing so is effective in getting them out of the poverty that often precedes having children outside of marriage," Williams said.

"It makes more sense to provide women with the resources and knowledge to prevent births that are not planned, which seems to be the most helpful in the long term. We can do that with comprehensive and early sex education and expansive and affordable access to birth control and family planning services."

Other countries similar to the United States are much more successful in keeping single mothers out of poverty. One recent study suggests that the poverty rate of U.S. single-parent households is nearly twice the average of 16 comparable countries.

"Paid parental leave and publicly funded child care for children under age 3 appear to be especially helpful in reducing poverty among single mothers," Williams said.

"These policies help single moms get and keep jobs, which was a primary goal of the 1996 welfare reform legislation. That should be our focus."

The second briefing paper released today by CCF was by Philip Cohen, professor of sociology at the University of Maryland. It is titled "Was the War on Poverty a Failure? Or are Anti-Poverty Efforts Swimming against a Stronger Tide?"