How do Barack Obama's criminal justice claims stack up?

President Barack Obama went to prison today -- as a visitor, and as part of his push for criminal-justice reform.

By traveling to a federal penitentiary in Oklahoma, Obama became the first sitting U.S. president to visit a federal prison. Earlier this week, Obama commuted the sentences of 46 drug offenders and formally launched his prison overhaul agenda, one of his last major legislative campaigns, during a speech to the NAACP’s national convention.

Prior to announcing his policy ambitions -- which include reducing mandatory sentences, increasing job training and restoring the voting rights of ex-felons -- Obama offered the audience a series of data-driven claims.

"In recent years, the eyes of more Americans have been opened to this truth, partly because of cameras, partly because of tragedy, partly because the statistics cannot be ignored. We can’t close our eyes anymore," he said in the July 14 speech.

Over the years, we’ve checked many statements about the U.S. criminal justice system. Some were echoed in the speech -- the excessive size of the prison population, the disproportionate rates of incarceration for minorities, and the costs and benefits of prevention as opposed to penalization.

Here’s a rundown of some of Obama’s claims in the speech, and what we’ve found in our past fact-checking:

"The United States is home to 5 percent of the world’s population, but 25 percent of the world’s prisoners."

We fact-checked a nearly identical claim by Democratic presidential candidate Jim Webb and rated the claim True.

"Our incarceration rate is four times higher than China’s."

We haven’t looked at this exact claim before, but it’s largely accurate, at least by one measure. In fact, Obama in his NAACP speech actually lowballed the comparison: By the measure he used, the incarceration rate of the United States is almost six times higher than China’s, which actually ranks below the world’s median.

On the other hand, if you measure by the sheer number of people, the U.S. prison population isn’t larger than China’s, Russia’s, and North Korea’s combined, as one Hollywood activist claimed. But the United States does have the second highest incarceration rate in the world. (Only the rate in the Seychelles is higher, but it’s considered an outlier.)

"Our prison population has doubled in the last two decades alone" and "quadrupled since 1980."

Data from the Bureau of Justice Statistics shows that the claim is slightly off. In 2013, there were 1.5 times more people behind bars than there were in 1992, and five times more than in 1980. Though his numbers are off by a bit, Obama’s overall point -- that we’ve amped up our rate of incarceration -- is correct.  

On his way out as attorney general for the Obama administration, Eric Holder said the federal prison population had recently decreased for the first time in three decades. We rated that claim True, but we did note that a rise in the state prison population wiped out that decline.

"African American and Latinos make up 30 percent of our population; they make up 60 percent of our inmates."

Combined, African Americans and Latinos make up 30.3 percent of the population of the United States, but they account for about 54.3 percent of the prison population. So the second part of Obama’s claim is a bit too high, but his overall point -- that the two minorities are disproportionately represented in prison -- has merit.

Others have made claims attempting to put these numbers in perspective. For instance, Republican presidential candidate Ben Carson said there more black young men in jail than in college today. PolitiFact Wisconsin rated that False.

Meanwhile, it’s been claimed that there are more African American men in the prison system now than were enslaved in 1850. We found that claim to be True. We also gave a True rating to the claim that the United States imprisons blacks at a higher rate than apartheid-era South Africa.

"African Americans are more likely to be arrested."

We’ve looked into a number of claims like this one. The NAACP’s New England chapter claimed that African Americans are arrested on marijuana charges at more than three times the rate of whites. PolitiFact Rhode Island rated that True.

Meanwhile, former New York City Mayor Rudy Giuliani made a statement to the opposite effect -- that black and white people who commit murder are convicted at the same rate. PunditFact rated that claim False. In another fact-check, we found that black men are about seven times more likely than white men to be arrested for murder.

"One study found that for every dollar we invest in pre-K, we save at least twice that down the road in reduced crime."

Obama made this claim in his 2013 State of the Union address, we rated that claim Half True.

"My administration has taken steps on our own to reduce our federal prison population. So I signed a bill reducing the 100-1 sentencing disparity between crack and powder cocaine."

Obama’s characterization of his record is accurate, but his original promise was to eliminate sentencing disparities entirely. In 2010, Obama signed a bill that reduced the ratio to 18-to-1, rather than the initial call of 1-to-1. We rated that a Compromise.