The details of President Obama’s acceptance speech at the Democratic National Convention on Thursday night are not known, but he’s been road-testing various claims about his record — and Republican challenger Mitt Romney — for months. Here are five dubious assertions the president frequently makes on the campaign trail.

Our goal is to help voters understand the context of these claims as they watch Obama’s address. We did a similar exercise last week in advance of Romney’s convention speech. He used three of the five examples we highlighted, as well as a variation of a fourth.

“Four years ago, I promised that I would cut middle-class taxes. And the average middle-class family, their taxes are about $3,600 lower than when I came into office. Now I want to keep taxes exactly where they are on the first $250,000 of everybody’s income.”

Obama mixes up some apples and oranges here. The $3,600 figure is over four years — $800 in each of 2009 and 2010 from the Making Work Pay tax credit and $1,000 in each of 2011 and 2012 from a Social Security payroll tax cut. Obama makes it sound as if that average family’s annual tax bill is now $3,600 less than it was under George W. Bush.

But the Making Work Pay tax credit has expired, and Obama has not promised to extend the payroll tax cut, meaning that people’s taxes will go up next year even if he succeeds in his effort to extend Bush-era tax cuts for those earning less than $250,000 a year.

“I’m also going to ask anybody making over $250,000 a year to go back to the tax rates they were paying under Bill Clinton.”

Here, Obama is defending his proposal to boost taxes on the wealthy by noting that the tax rate would be the same as under Clinton. The Bush tax cut set the top rate on income at 35 percent; Obama would restore it to the 39.6 percent rate set during Clinton’s presidency.

But while Social Security taxes are capped, there is no cap on Medicare payroll taxes. Obama does not mention that the health-care law included a 0.9 percent Medicare surtax on incomes over $200,000 for individuals and $250,000 for couples filing joint returns.

“Governor Romney brags about his private-sector experience, but it was mostly investing in companies, some of which were called ‘pioneers’ of outsourcing. I don’t want to be a pioneer of outsourcing. I want to insource.”

Here, Obama is referring to an article in The Washington Post that has been frequently exploited by his campaign. The article used the word “pioneers” but did not say that transfers of U.S. jobs took place while Romney ran the private-equity firm Bain Capital.

Instead, the article said that Bain was prescient in identifying an emerging business trend — the transfer of back-office, customer-service and other functions by companies willing to let third parties handle that business. Several of the companies mentioned in the article began by shifting work to other U.S. companies and grew into major international players in the outsourcing field.

Obama never mentions another Washington Post article, one that detailed how he has not been able to fulfill many of his campaign promises in 2008 to stem the outflow of American jobs to other countries.

“Nearly 7 million young people have health insurance because they’re able to stay on their parents’ plans.”

Obama has framed this assertion different ways, sometimes more accurately than the quote above.

The Department of Health and Human Services reported in June that more than 3 million young adults would not have health insurance without the health-care law. So how does Obama get to say that nearly 7 million “have insurance” because of the law?

That’s because he is relying on a private survey, published by the Commonwealth Fund, showing that 6.6 million young adults “stayed on or joined their parents’ health plans” in 2011.

Not all of these people were uninsured; some joined their parents’ plan for other reasons. The HHS report notes in a footnote, “This number exceeds our calculation because it includes some individuals who were already insured, often through their own private coverage.”

“Over the last 31 / 2 years, we have focused on righting the ship, making sure that we didn’t slip into a depression, saving an auto industry, creating 4.5 million new jobs, getting health-care done, helping young people go to college.”

The president loves this jobs figure — and it is has already been cited many times at the convention. But it is misleading, because it refers to private-sector jobs, not all jobs, and because it is based on a date (February 2010) that put the president’s jobs record in the best possible light.

The total number of jobs — private and government — created in the United States from February 2010 until now is 4 million. The job-growth number is still negative if you start counting from the beginning of Obama’s presidency.

According to the Bureau of Labor Statistics, job creation in Obama’s presidency is plus or minus a few hundred thousand jobs, depending on whether you date his presidency from January or February. At this point, Obama is on track to have the worst jobs record of any president since World War II.

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