As they struggle to hold onto Congress on Nov. 7 amid a wave of national discontent, Republicans are counting on their vaunted get-out-the-vote operation - which is built on such data mining.
Republican expertise in microtargeting is credited with helping reelect President Bush two years ago. This year, advisers to embattled Sen. Rick Santorum (R., Pa.) say that the party's high-tech turnout machine can bring him victory if the race with Democrat Bob Casey Jr. tightens.
"I truly believe we can move our numbers 4 to 5 points on Election Day," said Vince Galko, Santorum's campaign manager.
Though the GOP pioneered the practice, Democrats and their labor union allies are catching up in the microtargeting game, and both sides are hard at work in Pennsylvania, New Jersey and other states with Senate and House races that will determine which party controls Congress.
The heart of the Republican system is the Voter Vault, a database of 160 million Americans, updated with feedback from field canvassers and cross-indexed to reams of consumer data assembled from such things as public records, club memberships and retailers. Democrats have their own database, known as "Demzilla."
To build a microtargeting system, you start with a voter file that will include party registration and voting frequency. Then, you take a poll with a huge sample size to probe salient values and issues, and combine the results with census and consumer data to divide the electorate into like-minded "clusters." This information is supplemented with canvassing - and just before Election Day, campaigns begin contacting likely supporters again to get them to the polls.
