The team of reporters, researchers and editors across CNN listened throughout the debate, selecting key statements and then rating them True; Mostly True; True, but Misleading; False; or It's Complicated.
Hillary Clinton said, "Guns in and of themselves, in my opinion, will not make Americans safer. We lose 33,000 people a year already to gun violence."
As we first checked in October
, according to data from the Centers for Disease Control and Prevention, there were 33,599 people killed by firearms in 2014. However, the number includes suicides, unintentional deaths and incidents with undetermined intent as well as violence-related firearm deaths (homicide and legal intervention). In 2014, 11,409 people were killed in gun violence-related deaths by homicide or legal intervention. The CDC reports 586 unintentional deaths by firearms that year, and it also reports 270 deaths where the intent was undetermined.
Suicides accounted for almost two-thirds of the deaths by firearms.
More than 33,000 people did die in 2014 from firearm injuries. However, the number of people killed in violence-related homicides and legal interventions in 2014 was only about a third of that total.
Verdict: True, but misleading
Reality check: Clinton on drug prices
By Debra Goldschmidt, CNN
Clinton said, "I want Medicare to be able to negotiate for lower drug prices just like they negotiate with other countries' health systems. We end up paying the highest prices in the world."
Americans pay some of the highest prices for prescription medications -- two to six times more for brand-name prescription drugs
, according to the International Federation of Health Plans.
For example, the arthritis drug Humira costs Americans $2,246 for a one-month prescription, compared to $881 in Switzerland and $1,102 in England.
Medicare, the largest provider of medications, is prohibited from negotiating prices with drug companies
. Some lawmakers have argued this is what's behind the high prices.
The pharmaceutical industry group PhRMA says the high prices are due to the cost of research and development to bring drugs to the market.
Prescription drug spending increased 11.4% in 2014 and 9.6% in 2015 after steadily declining from 2000 to 2013, according to the Peterson-Kaiser Health System Tracker
The group attributes this to patents expiring and decreases in generic drug prices.
Reality Check: Clinton on states disinvesting from higher education
By Tami Luhby, CNNMoney
State finances were crushed in the wake of the Great Recession, which began in late 2007. States were forced to enact steep funding cuts, since they are required to balance their budgets annually.
On Saturday, Clinton said "states have been disinvesting in higher education." She's right: The ax fell heavily on higher education budgets, forcing public colleges in many states to hike tuition and fees.
Some 47 states spent less per student in the 2014-15 school year than they did in 2008, according to the Center on Budget and Policy Priorities, a left-leaning think tank. Only Alaska, North Dakota and Wyoming spent more.
States are spending 20% less per student than they did in the 2007-08 school year, on average, according to the center. In Alabama, Arizona, Louisiana, Pennsylvania and South Carolina, spending per student is down by more than 35%.
As a result, tuition at public colleges has soared. Tuition at four-year state colleges has risen by $2,000, or 29% percent, since the 2007-08 school year. In Arizona, tuition spiked more than 80%, while in California, Florida, Georgia, Hawaii and Louisiana, tuition is up more than 60%.
Most states have started spending more on higher education. The trend reversed in 2013, according to a report from the State Higher Education Executive Officers.
Some 35 states have increased higher ed budgets for fiscal year 2016, which started in July in most states, according to the National Association of State Budget Officers. Some 12 states have cut funding for colleges.
So while most states have a ways to go before they get back to pre-recession funding levels, the trend is for more spending on colleges.
Verdict: True, but misleading
Reality Check: Clinton on ISIS using Trump videos
By Kristen Holmes, CNN White House producer
Speaking about Donald Trump's proposed ban on Muslims entering the United States, Clinton said Saturday that ISIS was using video of the businessman to recruit fighters.
"They are going to people showing videos of Donald Trump insulting Islam and Muslims in order to recruit more radical jihadists," Clinton said of the GOP front-runner.
It is difficult to speak to all of ISIS' communication: Some of it happens in the open on social media sites, but other communications are hidden in what's known as the "dark Web."
While there have been some tweets and comments posted on ISIS-supported social media referencing Trump's rhetoric, according to information sent recently by SITE Intelligence Groups, there is no evidence that ISIS itself has released videos featuring Trump.
Neither ISIS' main media outlets nor any ISIS affiliates have used footage capitalizing on Trump's anti-Muslim language, according to Laith Alkhouri, the co-founder and director of Flashpoint, a group that monitors jihadist activity online. However, Alkhouri noted in comments to CNN on Saturday that Trump's comments do play directly into the recruitment playbook and he has no doubt they could eventually be referenced in official ISIS communications.
Alkhouri said the comments have also been mentioned in top-tier ISIS Web forums on the dark Web -- not heavily discussed, but they were definitely part of the "news feed, if you will," Alkhouri said.
The Clinton campaign directed CNN to an NBC News story published on December 8
, in which the executive director of the SITE Intelligence Group says of ISIS: "They love him from the sense that he is supporting their rhetoric."
"They follow everything Donald Trump says," Rita Katz told NBC. "When he says, 'No Muslims should be allowed in America,' they tell people, 'We told you America hates Muslims and here is proof.'"
Ultimately, however, there is no evidence of ISIS using videos of Donald Trump for recruitment.
Reality Check: Clinton on campaign contributions
By Kate Grise, CNN
Clinton claimed that a review of OpenSecrets.org would show that 3% of her donations have come from people in the finance and investment world and that more of her donations have come from students and teachers than those associated with Wall Street.
The website Opensecrets.org
includes the most up-to-date filings by each candidate's campaign and associated groups, according to the site.
According to the site, Clinton's campaign committee, Hillary for America, has raised more than $77 million. Donations from those in the education industry totaled $1.9 million. Those associated with the securities and investment industry and finance industries gave the campaign committee more than $2.9 million. While the Wall Street crowd gave more than those in the education industry, Clinton is only slightly off saying 3%, since Wall Street donations actually make up 3.76% of donations her campaign committee has raised.
But the campaign committee is not the whole story when it comes to giving in support of Clinton's campaign. There are super PACs and hybrid PACs also working to support Clinton.
According to OpenSecrets.org, donors associated with securities and investments have given more than $5.5 million to Clinton's campaign committee and associated super PACs and hybrid PACs working on her behalf. Another $1 million was given by those associated with miscellaneous finance industries.
Those PACs and Clinton's campaign committee have raised almost $100 million for Clinton's efforts, so those associated with the "finance and investment world" donated 5% of Clinton's total contributions. Almost all those contributions from the education industry went to the campaign committee, about 2% of total giving.
There are some potential problems with the Opensecrets.org data that Clinton cited:
According to Opensecrets.org, only about 60% of the total contributions were coded to include the donors' occupations and make it possible to determine which industry they are associated with. According to federal campaign finance regulations, only donations of more than $200 must include the donor's occupation, but that information is self-reported.
OpenSecrets.org does not publicly report the number of donations by industry, only the giving totals.
Donors from the securities and investment industry, as Opensecrets.org categorizes them, work largely for hedge funds, private investment firms, stockbrokers and bond dealers. Donors from the education industry cited by Opensecrets.org included individuals associated with universities and schools.
Based on total giving amounts, Clinton's statement that more students and teachers give to her than people in finance is False. Likewise, based on total giving, her claim that those in finance and investment gave only 3% is also False.
Reality Check: Sanders on regime change
By Kevin Liptak, CNN White House producer
Clinton and Bernie Sanders squabbled over each other's records on supporting regime change in dictatorships.
Sanders asserted that Clinton's 2002 vote to authorize war in Iraq led to Iraq's current dire state and said the military push to rid Libya of tyrant leader Moammar Gadhafi created a the power vacuum currently being exploited by ISIS.
"Our differences are fairly deep on this issue," Sanders said about Clinton. "I worry too much that Secretary Clinton is too much into regime change and a little bit too aggressive without knowing what the unintended consequences might be."
Sanders, as he notes often on the campaign trail when drawing contrasts with Clinton, did vote against authorizing force against Saddam Hussein in 2002, and he was a vocal opponent of U.S. military action in Libya.
But he is on record in earlier instances supporting regime change in those countries.
As a congressman, he voted in 1998 for a resolution that "reaffirms that it should be the policy of the United States to support efforts to remove the regime headed by Saddam Hussein from power in Iraq."
And despite his criticism of Clinton's handling of Libya, he supported a congressional resolution in 2011 that called on Gadhafi to "desist from further violence, recognize the Libyan people's demand for democratic change, resign his position and permit a peaceful transition."
Those point to a record of supporting regime change, even if he later opposed U.S. military action as means to those ends.
We rate his claim that his previous record is different from Clinton's in supporting regime change as False.
Reality Check: Sanders on gun ownership in Vermont
By Lisa Rose, CNN
Sanders said that more than half of the people in Vermont are gun owners, and he added that New Hampshire has a similar number of residents with firearms.
It's difficult to say where Sanders got those statistics, because the government does not track and publish gun ownership rates per state. The most reliable information available is from a 2015 study in the journal Injury Prevention
. According to the study, 28.8% of Vermonters are gun owners and 14.4% of New Hampshire residents own guns. Just six states -- West Virginia, Arkansas, Montana, Wyoming, Idaho and Alaska -- have gun ownership levels greater than 50%, according to the report.
One caveat: Although the study was published in 2015, the statistics are based on a survey conducted in 2013.
Reality Check: Sanders on universal health care
By Debra Goldschmidt, CNN
Sanders said, "We're the only major country on Earth not guaranteeing health care to all people."
This is something he's said before
, including to ABC News in July.
The World Health Organization issued a report in 2014
saying, "the USA is currently the only high income country without nearly universal health care coverage."
Reality Check: O'Malley on Clinton's and Sanders' gun positions
By Chip Grabow, CNN
Martin O'Malley called out what he claimed were Clinton's and Sanders' inconsistent positions on gun control.
O'Malley went after Sanders' gun control record, saying: "Sen. Sanders voted against the Brady Bill. Sen. Sanders voted to give immunity to gun dealers. And Sen. Sanders voted against even research dollars to look into this public health issue."
First, on O'Malley's critique of Sanders' record regarding the Brady Bill, which became law in 1993: There were various congressional votes on the bill during its creation, the first of which came in 1991. Sanders was elected to the House in 1990 and his voting record during the evolution of this bill is a consistent "nay." In 1991, Sanders voted against a draft that called for a seven-day waiting period for background checks. Later that year, a new version came back to the House and Sanders voted against it. In 1993, another draft came back up for a House vote and Sanders voted against it. Finally, when the Brady Bill returned for a final vote in late 1993, it passed and became law, but Sanders voted against it.
Regarding O'Malley's claim that Sanders gave immunity to gun dealers: He was referring to a vote in 2005 over a bill (the Protection of Lawful Commerce in Arms Act) that gave protection to firearms manufacturers and dealers from being held liable when crimes were committed with their products. Sanders indeed voted in favor of the bill.
Finally, in 1996, Sanders voted against an amendment in the federal budget that would have provided funding for gun research.
O'Malley also went after Clinton's gun control record. He said she changed her position from calling for federal regulations in 2000 to a different stance in 2008, while running against Barack Obama, when she said regulations at the federal level weren't the answer.
In fact, in 2000, Clinton endorsed a bill that would require licensing and registration of handguns, saying, "I also believe that every new handgun sale or transfer should be registered in a national registry."
During the 2008 Democratic primary, Clinton appeared to back off from that earlier call for federal regulations, saying, "I don't want the federal government pre-empting states and cities like New York that have very specific problems."
It's also been noted that Clinton tried to appeal to Second Amendment supporters during her 2008 campaign, pointing out how her dad taught her how to shoot when she was a little girl. She stated in a 2008 Democratic debate that "there is not a contradiction between protecting Second Amendment rights" and the effort to reduce crime.
Based on Sanders' and Clinton's stated positions or votes related to gun control, we determined O'Malley's claims to be True.
Reality Check: O'Malley on U.S. investment in intelligence
By Gregory Wallace, CNN
Since the 9/11 attacks in 2001, the U.S. hasn't stepped up to the threat of terrorism, O'Malley said.
He spoke of "a lack of investment that we have as a nation failed to make over these last 15 years in intelligence gathering, intelligence analysis, intelligence sharing."
The shortcoming, he said, is "not only in (the) theater -- in Syria and Iraq and other places where we involved ourselves in toppling dictators without having any idea what comes next -- but here in the homeland, as we protect people from this threat of the lone wolves and these changing tactics and strategies."
At the first Democratic debate, back in October, O'Malley made a similar claim: that the U.S. had "failed as a country to invest in the human intelligence," a claim he also made Saturday night. CNN rated that claim as "True" back in October.
Is he right that the federal government has underfunded homeland security? Here are the numbers.
The Department of Homeland Security, created in response to the 2001 terror attacks, had a budget of $39.7 billion for the last fiscal year, which ended in September. That's an increase from the department's first budget of $31 billion in 2004.
Spending on intelligence in other parts of the federal government is up, too.
The National Intelligence Program budget has grown by more than $10 billion since 2005, according to numbers compiled by the Federation of American Scientists.
It is true that intelligence spending has slipped in recent years since peaking in 2011. The most recent budget, for the fiscal year that ended in September, was $50.3 billion.
Spending on military intelligence programs has followed a similar trajectory, according to the data compiled by FAS.
Details of how the funds are spent generally isn't available, due to the secrecy of intelligence programs. And while spending is up, there is an active debate over how the investments should be made.
This fall, Congress passed reforms to data collection programs in the Patriot Act, and questions have been raised about how authorities missed the terrorists who killed 14 people in San Bernardino, California, earlier this month.
The FBI recently said it has 900 open investigations into possible cases of homegrown extremists, including many believed to have links to ISIS.
While the efficacy of the investments is in question, it is clear the federal government has substantially increased spending on homeland security and intelligence gathering.