How Projections Are Made

Nov. 7 , 2006 — -- ABC News relies on a team of social scientists and journalists to project election winners. This team, called the Decision Desk, is overseen by three experienced decision makers, all of whom hold Ph.D.s in the social sciences and are experts in quantitative methods.

To project a race, the Decision Desk analyzes exit polling and actual vote data using a variety of statistical models. The Decision Desk waits until the models indicate that there is at least a 99.5 percent certainty that the leading candidate is the winner. The team also considers the possible impact of absentee and early voters and a number of other factors, which vary by state

If It's Too Close to Project
ABC News will not project any races where the margin between the candidates is less than one percentage point in the tabulated vote, even if 100 percent of the precincts have reported. This is because many votes may be outstanding even with 100 percent of precincts reporting (e.g., absentee and provisional ballots). Also, the county vote data on election night are unofficial tallies, so there may be errors that could affect the results in a close race.

Data Sources
Voter News Service was disbanded after the 2002 elections. The National Election Pool was formed in its place by ABC, NBC, CBS, Fox News, CNN and The Associated Press. The NEP has hired Edison/Mitofsky to conduct exit polling and projection modeling. The projection models have been improved since 2000 based on an extensive review by the NEP members and outside experts. Since 2000, the NEP has also added more telephone polls, to be conducted by Edison/Mitofsky, in states where absentee and early voters (who won't vote at the polls on Election Day) are expected to represent a significant part of the vote.

ABC has worked closely with Edison/Mitofsky since early 2003 and used its election system for coverage of the 2004 Democratic Primaries and General Election.

In addition, AP provides ABC with county vote tabulations, which are also fed into the projection models. The AP's experience tabulating the vote dates to the 1800s.