WASHINGTON—Did Vice President Joe Biden really call for a new global business tax on U.S. companies operating abroad? Could it be true that half of high school students in the 50 largest cities don't graduate? And is President Barack Obama pushing Roman Catholics to "violate the tenets of their faith" with his expansion of mandatory contraception coverage?

Republican presidential candidate Mitt Romney was on shaky ground Friday with his accusation about birth control, because Obama backed down from forcing religious-affiliated employers to offer contraception coverage in a compromise devised to placate the church. On education and taxes, he was more on point.

A look at those claims in his speech to the National Rifle Association and how they compare with the facts:

ROMNEY: "Today half the kids in our 50 largest cities won't even graduate from high school."

THE FACTS: Bleak but mostly true, according to a study by America's Promise Alliance, a children's advocacy group founded by former Secretary of State Colin Powell. Romney did not directly blame Obama for that; he couldn't, because the research mostly predated his presidency.

But it found that only 53 percent of all young people in the 50 largest cities were graduating from high school on time. That was well below the national average of 71 percent.

A subsequent report by that and other groups found improvement overall, with the national graduation rate rising to 75.5 percent in 2009, but it did not break down the 50 cities.

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ROMNEY: "Now the Obama administration has decided that it has the power to mandate what Catholic charities and Catholic schools and Catholic hospitals must cover in their insurance plans for their employees. It's easy to forget how often candidate Obama assured us under Obamacare, nothing in our insurance plans would have to change. Remember that one? Well, here we are just getting started with Obamacare and the federal government is already dictating to religious groups on matters of doctrine and conscience."

THE FACTS: If that administration thinks it has that power, it at least decided not to exercise it. Under pressure from Catholic bishops and others, the administration changed its proposed policy so that religious employers could opt out of having to cover contraception, but women who work at such places would still be assured of getting free coverage if they want it through the insurers instead.

This mollified some, though not all, critics.

Houses of worship were never going to be forced to offer contraception coverage. Instead, nonprofit institutions affiliated with a religion, like Catholic hospitals, were to be required to cover birth control as part of a package of preventive services for women. But that sparked a backlash and Obama sought the middle ground, a development that Romney skipped past in his NRA remarks.

Recently, the administration offered options to help insurers offset the costs of the coverage, perhaps by giving them credits against fees they have to pay under another part of the health care law. The idea is to discourage insurers from trying to recoup the money from religious institutions that object to birth control. The likely bottom line: Taxpayers will help pay for it.

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ROMNEY: "The vice president has now proposed a new global business tax."

THE FACTS: Indeed he has. Obama wants tax breaks for domestic manufacturing and tax penalties on U.S. companies that outsource jobs and production. That's essentially a new tax, with a global reach, and Biden was happy to call it such in Iowa last month.

"We want to create what's called a global minimum tax," he said.

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Associated Press writers Ricardo Alonso-Zaldivar, Ben Feller and Kimberly Hefling contributed to this report.

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