To land an invite to the debate, candidates needed to hit 5 percent in four polls approved by the DNC, either nationally or in one of the four early states (Iowa, New Hampshire, Nevada and South Carolina) or 7 percent in DNC-approved polls conducted in the early states.

Additionally, candidates needed to receive contributions from 225,000 unique donors (with 1,000 donors in at least 20 different states, territories or D.C.).

Yang’s campaign said he easily cleared the donor threshold. But he did not hit the polling threshold, hitting 5 percent in an approved poll twice — including in the last poll released in the qualification window, a Des Moines Register/CNN/Mediacom Iowa poll released Friday night.

Also missing from the stage are candidates like Sen. Cory Booker of New Jersey and Rep. Tulsi Gabbard of Hawaii. Booker had cleared the donor threshold and Gabbard was within striking distance, but neither of them hit five percent in any approved polls.

CNN and the Des Moines Register, the co-hosts of the Jan. 14 debate, announced a podium order based off the average of qualifying polls released in January. From left to right, as the audience will see the candidates: Steyer, Warren, Biden, Sanders, Buttigieg, Klobuchar.

The debate starts at 9 p.m. Eastern Time from Drake University in Des Moines, airing on CNN and streaming online.

Booker and Yang, in particular, agitated for changes to the debate process as their risk of missing the stage drastically increased. After a month-and-a-half long early state polling drought, six early-state polls were released this week (with at least one in each of the states).

"If the DNC had only done their due diligence and commissioned polls in the early states, Andrew Yang would certainly be on the debate stage next week," Yang campaign chief Nick Ryan said in a statement on Saturday, citing what it said was internal polling data showing Yang at 5 percent in early states. "The DNC tried to run this same play in 2016, and they paid for it with a loss in the general."

Internal polls do not count toward debate qualification, and it would be incredibly unusual for a party committee to conduct polling for public consumption, as the Yang campaign requested the DNC do.

In public, independent polling released in both of those states this week, Yang did not hit 5 percent. In a CBS News/YouGov poll in New Hampshire, Yang was at 2 percent, and 3 percent in a New Hampshire Monmouth poll. In a Fox News Nevada poll, he was at 4 percent.

Another big candidate missing from the stage is former New York Mayor Mike Bloomberg. Bloomberg easily cleared the polling threshold but couldn’t qualify because he is not accepting contributions, instead choosing to fund his campaign solely from his massive fortune.

The decision has irked some of the other contenders, who argue he is running an imperial campaign where he doesn’t engage his rivals or defend his ideas (for his part, Bloomberg maintains he would participate in a debate if the rules allowed him to do so without collecting donations).

The other candidates who will not participate in this debate are former Massachusetts Gov. Deval Patrick, Sen. Michael Bennet of Colorado and former Rep. John Delaney of Maryland. Patrick, who launched his campaign in November, has not been invited to any of the debates, while Delaney and Bennet have not been on stage since the early rounds.

Next week's debate is the seventh in a series of twelve planned debates. The next three are all scheduled for February: Feb. 7 in New Hampshire, Feb. 19 in Nevada and Feb. 25 in South Carolina.

The DNC has not announced how candidates can qualify for future debates, although DNC Chair Tom Perez has hinted the party committee is considering changing the criteria for the stage once voters actually start voting.