Conservatives are once again touting marriage as the way out of poverty. They point to U.S. census data showing that poverty is concentrated in single-parent families and that marriage is highly correlated with more successful households and higher-achieving children.

Not so fast. Marriage by itself doesn’t lift people out of poverty — certainly not as well as policies that encourage and enable parents to work.

Equally important, correlation isn’t the same as causation. If it were, we’d be celebrating the decline of marriage. After all, in the past 50 years, poverty has decreased along with the rate of marriage.

The conservative argument, at any rate, is largely definitional. The government set the 2013 poverty level at $15,510 for a single parent with one child. If that parent married another single parent, and they each earned a below — poverty $15,000, their combined income of $30,000 would automatically put them above the official poverty line of $23,550 for a family of four.

What’s more, past attempts, notably by the George W. Bush administration, to boost marriage rates with grants to state marriage-skills programs haven’t worked. Long-term trends toward fewer marriages prevail across incomes, cultures and countries.

In some circumstances, marriage may even be the wrong answer. Is it better, for example, to raise children in a home where the two parents are constantly fighting? In one study of single mothers, more than two-thirds of those who married ended up divorced by the time they were 35 to 44, at which point they were worse off economically than if they had stayed single.

It’s also possible that the absence of marriage doesn’t cause poverty but that poverty causes less marriage. Black women, who make up a disproportionate number of single mothers, tell researchers they would like to be married but too often that means having another mouth to feed. To a statistician, marriage may make sense, but to many women, it doesn’t.

Sen. Marco Rubio of Florida, the Republican presidential aspirant who has taken up the issue, is right to worry about the consequences when children are raised by poor, single parents. But if we’re to be guided by the data, he could just as well tell parents “Go to college” as “Get married.” In 2009, the median income of families headed by a parent with a college degree was $100,000. The median income of households headed by a high-school dropout was $31,000.

What must come first are investments in poor children, regardless of their parents’ marital status. The United States needs policies that encourage kids to stay in school, and parents to work, and then supplements the incomes of the working poor. This path has more bipartisan support than direct cash benefits to able-bodied adults do.

And it works, as President Bill Clinton’s welfare reforms demonstrated. Two other programs, the child tax credit and the earned income tax credit, have reduced poverty more than any other federal program except Social Security. Because they are available only to workers, the tax credits encourage parents, single or not, to stay employed. And because the credits are refundable, even those with no income-tax liability benefit.

In his State of the Union speech this week, President Barack Obama was right to propose an expansion of the earned income tax credit to help childless workers who now qualify for only a minuscule sum. Rubio supports the concept, having proposed direct wage subsidies for all working poor adults, including the childless. So long as Rubio doesn’t envision cutting benefits to working parents in order to cover childless adults, it seems there are grounds for a Rubio-Obama deal.

In some cases, of course, marriage can benefit working parents. But there are more effective and efficient ways for the government to reduce poverty. To suggest otherwise is to engage in a false debate.