Faced with the possibility of another close election, U.S. political campaigns and advocacy groups are drawing up detailed profiles of the voters who will determine their success at the polls next fall.
Political groups are finding out what kind of car their prospective supporters drive, how much they earn, what sort of neighborhood they live in and what magazines they read.
They may not know how individuals voted in the last election, but they do know who showed up at the polls and whether they are registered with a particular party -- strong indicators of how they are likely to vote in the November election, experts say.
"It's pretty scary, the stuff you can get on people," said Robert Richman, founder of the liberal campaign consulting firm Grassroots Solutions.
Political groups say such "voter targeting" allows them to organize voter-registration drives, communicate with supporters and sway undecided voters to their cause.
But such tactics lead to ideological polarization and declining voter turnout as campaigns tailor their message to a dedicated core of likely supporters, some critics say.
"Elections are supposed to be about the give and take of political ideas, but increasingly elections are about going out and trying to get market share," said Kim Alexander, president of the California Voter Foundation, a nonpartisan public interest group.
The raw data for much of this activity flows through a rickety row house tucked behind the U.S. Capitol, where Aristotle International Inc. compiles and constantly updates a list of some 160 million voters.
On a recent afternoon, company President Dean Aristotle Phillips searched the voter database for Democratic women between 35 and 45 years old in Fairfield County, Connecticut, who have indicated they don't want to receive telemarketing calls.
The computer returned 3,004 matches, with a long list of personal details: name, address, phone number, income level, whether they have children, household size, whether they have an "ethnic" surname. Contributions to political candidates, arts organizations, environmental groups and other interest groups were also noted.
Most valuable is the voter history, which reveals how many elections the person has participated in since 1984. Reliable voters are especially prized, Phillips said.
"A voter who voted in every single election in the past 10 years is more likely to show up on polling day," he said.
Nearly half of the 535 members of the U.S. Congress buy voter data from Aristotle, along with state legislature candidates, party organizations and interest groups like the NAACP at a rate of $25 per 1,000 names.
Campaigns can then augment that data with car registration records, home sale records and magazine subscriptions to determine who is worth contacting.
A registered Democrat who votes regularly and has donated money to abortion rights causes will probably be receptive to other liberal causes, while the National Rifle Association might be interested in a list of people who have taken out hunting licenses to expand its membership base, experts said.
Many political groups are reluctant to reveal techniques for fear they could be adopted by the other side.
"The less that's revealed to the Democrats, the better," said Christine Iverson, a spokeswoman for the Republican National Committee.
Detailed voter databases allow campaigns to save money on postage by sending mailings only to those households that might be receptive. Volunteers going house-to-house can know whether to knock on a door or pass it by.
"Campaigns have limited resources," Grassroots Solutions' Richman said. "It doesn't make sense to try to talk to everybody."
But if candidates are only speaking to their most loyal supporters, those who may not fall neatly on either side of the ideological divide may be overlooked, Alexander said, noting that voter turnout has declined steadily.
"There are the American people and there are the American voters, and they are not one and the same," she said.