The “get out the vote” effort in the US is massive, turning otherwise healthy political parties into quite sophisticated stalkers. Both parties now compete to maintain minutely detailed files on every voter in the country.

At the most basic level, they detail likelihood of voting and which direction they’ll cast their ballot. On election day, this targets the efforts of thousands of volunteers who will be making phone calls and knocking doors to drag out every last supportive vote.

While these databases were originally primarily used for “get out the vote” efforts, now knowing who someone is leaning towards is no longer enough — strategists have to know why.

Details stored now go well beyond name, age and party affiliation. Databases track voting histories, levels of disposable income, the type of car someone drives and even the kinds of foods they prefer. Computer algorithms scan names to tag likely religions and ethnicities, separating the Smiths from the Goldbergs and Martinos.

Information pulled from public records is used to establish a voter’s names, age, addresses and phone number. But records also show voting histories, so we know whether you voted in the primaries, for the school board, or whether you only show up occasionally in presidential years. Other archives can show what car you have registered and how many guns you own.

This can help build up pictures of households, so we know if your kids are still in school, off to college, or whether you’re looking after elderly parents. Overlaid with this is information from commercial data miners, who can provide lists of magazine subscriptions, personal interests and levels of disposable income.

The campaigns themselves will then add further information. In the months before an election, armies of volunteers call voters and knock on doors. After each encounter, the volunteer will estimate a person’s level of support and enthusiasm, which will then be added to their file. There’s even a freely available iPhone app which provides the details of everyone registered near your location, with fields for volunteers to upload further information after contact.

Campaign websites will ask voters to login through Facebook, or sign up to email lists, providing even more information for the databases. If you go on to sign an online pledge for a specific cause, from gun rights to women’s rights, your file will be tagged with the issues you care about. If you’ve made donations, or clicked on links from campaign emails, this will also be tracked. Your level of motivation and the type of messaging you respond to will be marked in your file.

Recently, the Democratic campaign asked supporters to write messages online about why they supported Barack Obama — more information which can be scanned for key words to build up even more comprehensive files.

The databases themselves are provided by two partisan companies. The National Geopolitical Voter Activation Network supports the Democrats, while Republicans use Voter Vault. Each company sells access to party committees, advocacy groups and candidates running for office up and down the ticket. Whether you’re running for POTUS, or your kid’s local school board, the data goldmine is only a licence fee away.

It’s these companies who are reaping the benefits of a nation which has turned democracy into an industry. This year, the combined spending of presidential campaigns, congressional campaigns and the plethora of local and state elections will amount to well over $5.5 billion.

And with 50 states running in their own election cycles, Congress up for election every two years, and organisations constantly campaigning on ballot measures, there’s a steady stream of money and campaigns helping with data entry even outside of the presidential years.

This data can be powerful if used correctly. Not only can it build up general pictures of the electorate, it can also be used to send out narrowly targeted messaging which might otherwise be a waste of money, or actually lose votes if seen by the broader public.

The 2004 Bush campaign used information to create categories of voters to target messaging on, from “tax and terrorism moderates” to unenthusiastic conservatives that could be persuaded by pro-life or anti-gay messaging. By 2008 the Democrats had caught up, with Barack Obama’s targeted grassroots campaign mobilising impressive voter turnout and motivating millions of non-voters not only to register, but to also show up at the polls.

With memories of the debates and conventions fading, a daily stream of inconsistent polls shows an almost manic-depressive and evenly-split electorate, both nationally and in key swing states. All signs point to it being a close run thing.

How effectively each campaign can motivate their base to get out and vote, especially in the battleground state of Ohio, will be a deciding factor over wins the White House on November 6. This election, more than any other, could come down entirely to the quality of voter data, and the effectiveness of the “get out the vote” efforts it powers.

*Ben Winsor is an Australian law and international studies graduate working with a New York political consulting firm assisting with a Democratic congressional campaign in New Jersey, and in his spare time volunteers for the Obama/Biden campaign