Primer: What To Expect On Caucus Night

Map of Iowa over white house and US Flag
By Kathy Frankovic, CBS News director of surveys

On January 3, the delegate selection process begins -- long-awaited by many, including many who just want the pre-campaign period to end!

The process begins with the exception - a caucus, not a primary. Even within this exceptional state, Republicans and Democrats do things differently. And whatever happens on January 3, Iowa's final decision on who goes to the Conventions isn't made until the state convention on June 15.

Here's what to expect on caucus night.

WHO CAN VOTE: Caucus-goers must be residents of the precinct where their caucus is being held and be at least 18 years old as of November 4, 2008 (born on or before November 4, 1990). There is no absentee voting, so participants must actually attend the caucus where they live.

Caucus-goers must be registered to vote with the party whose caucus they are attending. But both parties allow registration and changes of party on caucus night. .

WHERE THEY VOTE: There are 1,784 precinct locations for each party - so more than 3,500 caucuses will take place.

HOW REPUBLICANS VOTE: After taking care of some party business, Republicans will cast votes in a non-binding straw poll. This will mainly be done by secret ballot, with Iowa Republicans indicating their preference for the nomination. Later, everyone at a caucus will vote for delegates to represent them at the March 8 Republican county conventions.

HOW DEMOCRATS VOTE: Democrats will "caucus" by organizing in groups supporting each candidate (the "first division" or the "pre-viability" count). Candidates must have a minimum number of supporters (usually 15% of the total number of attendees) at a caucus in order to elect delegate to the March 15 Democratic county conventions. Supporters of those who have not met the minimum are given the opportunity to join other "viable" groups. Other voters can also change their preferences.

Once the number of county convention delegates allocated to each candidate is determined, then each of those candidate groups selects those delegates.

WHAT WE WILL KNOW AT POLL CLOSING TIME: There will be an entrance poll conducted at 40 caucus sites for each party. The one-page questionnaire of voters entering the caucuses will ask their preference, what motivated their choices, and their own characteristics.

8 p.m. Eastern time: The caucus doors will be closed, and we will be able to report some early findings from those entrance polls.

Since the Republicans have only the straw vote, when we can project a winner of that straw vote, we will.

The Democrats' process is more complicated, and the entrance polls will only be able to tell us which who (one candidate or several candidates) was leading among voters going into the caucuses.

WHAT WE WILL KNOW LATER IN THE EVENING: The Iowa caucuses are run by the state parties. Each party counts something different: the Republican Party will tally the straw poll results, while the Democratic Party will count what happens at the end of the process - the number of delegates elected to go to the county conventions. .

When we learn enough about those delegate totals, we will project a winner of the Democratic caucuses. The Democratic winner is the person who collects the most delegates to the next stage of the Iowa process.

EVEN LATER IN THE EVENING: We will have an estimate of how many delegates to the Democratic National Convention a candidate has won. These delegates will be added to the CBS News delegate estimate.

No delegates will be allocated to the Republican Convention.

ENTRANCE POLL ANALYSIS: Throughout the night, the entrance poll will help us understand the reasons a candidate won - giving us data about who supported which candidate and why,

In 2004, the Democratic entrance poll told us that 41% of Democratic caucus-goers made their minds up in the last week of the campaign there. So there is a lot that can happen between now and January 3.