How Exactly Do The Iowa Caucuses Work?

By Domenico Montanaro

Published January 30, 2016 at 8:08 AM EST

Precinct Chairwoman Judy Wittkop explains the rules during a 2008 Democratic caucus in Le Mars, Iowa.

Iowa's process of picking its choice for president is complicated. We try to demystify it in this space.

Here are the basics:

Where does the word "caucus" come from?

The word "caucus" is thought to come from an Algonquin Indian word — cau´-cau-as´u, meaning "one who advises, urges, encourages" and "to talk to ... give counsel, advise, encourage, and to urge, promote, incite to action."

What is a caucus and how does it work?

The short answer

It's essentially a neighborhood meeting of sorts — for politically active, like-minded people. Unlike the kind of voting most people are used to — which takes only a few minutes and involves pushing a button or pulling a lever in the secrecy of a voting booth — Iowans have to devote an hour or so of their evenings to the process. The caucuses on the Democratic side are also much more out in the open — everyone knows whom you voted for and possibly why. This is why ardency of support is important. In Democratic caucuses, you don't vote with your fingers; you vote with your feet. (More on that in our long answer below.) For Republicans in Iowa, the process is much simpler and more orderly. Someone from the campaigns might speak for a particular candidate, but then voting happens by an informal secret ballot. Think: folded-up pieces of paper passed in and collected.

The long answer

The official caucus math worksheet on the Democratic side that has been used in years past.

Democrats: 1,683 Democratic caucuses will be held at more than 1,000 locations. They start at 8 p.m. ET and can last an hour or more. There are 44 delegates to the national convention that can be won through this process, which takes months. None are assigned on caucus night. Note: Eight more unpledged party leaders and elected officials get to go straight to the national convention from Iowa. They don't have to go through the state's complicated delegate selection process — and they can vote for whichever candidate they want at the convention. Because of that power, they're colloquially referred to as "superdelegates."

Here's what happens on caucus night:

There's a call to order.

A caucus chair and secretary are elected.

Supporters make the case for their candidates.

Caucusgoers separate into groups in corners or parts of the room for their candidates of choice. (It's kind of like a junior high dance, if the kids weren't so petrified of each other.)

When the groups are formed, the elected chair adds up how many supporters are in each cluster.

Each candidate has to meet a viability threshold of 15 percent. That means the number of people in the cluster has to be at least 15 percent of all the participants in the room. (This has the most relevance this year to former Gov. Martin O'Malley, D-Md., who hasn't polled above single digits in the state. If there are 100 people caucusing and, of them, 14 or fewer say they're voting for O'Malley, then O'Malley would get zero delegates out of that precinct.)

If a candidate is determined not to be viable, that candidate's supporters have to choose another candidate. In the example above, O'Malley's 14 people have to "re-caucus" and can choose Sanders or Clinton (or someone else who clears the threshold).

During the re-caucusing process, supporters from the viable candidates try to sway the nonviable candidate's voters to their side.

Once the re-caucusing is settled and all remaining candidates are deemed viable, the numbers are tallied. (This year, those results will be sent in using an app built by Microsoft.)

Delegates and alternates are selected to attend county conventions.

Party business is conducted, including elections to committees, and platform resolutions are introduced.

The 1,683 precinct caucuses produce 11,065 delegates. They are eventually filtered to 44 national convention delegates after county (March 12), congressional district (April 30) and state (June 18) conventions. They are not related to the caucus night vote in any way except to nominate that first round of 11,065.

For a quick explainer of what happens on the Democratic side (using Legos), check out this video from our friends at Vermont Public Radio:

Iowa's 52 total delegates to the national convention represent just a tiny fraction (about 2 percent) of the 2,382 delegates needed to become the Democratic nominee.

If it's such a small percentage, then why all the attention? This is all about momentum. For perspective on how vital these early contests can be, just one person in the past 40 years — on either side — has lost both Iowa and New Hampshire and gone on to be president: Bill Clinton.

You won't see actual raw vote totals or raw vote percentages on election night. To make matters even more confusing, when you see the reported percentages of who won and lost, what you're actually looking at are what's known as "state delegate equivalents." That's a complicated phrase for the number of delegates sent to the next round (to those county conventions) and tallied up with those worksheets/Microsoft app.

What does this mean in practice? It can give candidates whose vote share isn't concentrated in population centers an advantage. That's a potential problem for Vermont independent Bernie Sanders, who is drawing big crowds from college towns. It's why the Sanders campaign has encouraged those college kids to go back home and caucus to spread out the vote.

Republicans: GOP caucuses will be held at about 700 locations. They also start at 8 p.m. ET and last about an hour. Thirty delegates are at stake of the 1,236 needed to be the GOP nominee.

Here's what happens on caucus night:

There's a call to order.

A caucus chair and secretary are elected.

Presidential candidate representatives speak and make their case.

Caucusgoers pick a candidate through paper ballot. In past years, depending on the size of the caucus, this could have been done through a show of hands. Unlike Democrats, the Republicans have no 15 percent threshold.

Votes are tallied and reported to party headquarters. After problems in 2012, this will be done through a Microsoft-developed app, which Democrats are using, too.

Delegates are elected to attend county conventions. This year, in a change from past years, delegates will be affixed to candidates based on the proportion of votes respective candidates receive statewide. This, like the new reporting process, was also the result of problems in 2012. The national party mandated that all states that hold contests before March 15 have to bind their delegates to candidates.

Alternates and junior delegates are elected. (Junior delegates are under 18. Consider them apprentice caucusgoers.)