Getting inside the heads of US voters

This is where so-called microtargeting comes in – there is a vast and growing industry in the US that collects data on citizens, culling information from public records, such as voter registration records and gun licence applications, as well as private databases owned by direct mail marketers, magazine publishers, “loyalty-card” operating retail giants and the financial industry, which assiduously tracks credit scores. (This is not to mention the goldmine that is Facebook, which will undoubtedly play an increasingly prominent role in the data-harvesting trade in years to come.)

Collating and analysing this data, campaigns can search for patterns and correlations, allowing skilled analysts to extrapolate a frighteningly accurate picture of any given voter’s values, priorities, even their likely level of political engagement.

The result is the ability to identify the interests of individual voters and tailor campaign messaging specifically for each one of them.

“At the core of microtargeting, and what the Obama campaign really refined, is looking at the interplay between all these thousands of variables, and using it to arrive at a unique prediction for each voter’s behaviour,” Issenberg explains.

“What the Obama campaign did was, through these scores, come to a prediction of your likelihood as a voter of turning out to cast a ballot at all, or of supporting Barack Obama, or holding a particular position on abortion, for instance.

“By updating those weekly, they were able to have a really molecular interaction with the electorate.”

The effect was largely invisible to those of us following the race between Obama and John McCain, but it was nonetheless tangible. “I quote Ken Strasma, who was Obama’s top microtargeting consultant in 2008, and he said, ‘We knew who people were going to vote for before they did’,” says Issenberg. That’s an unimaginably powerful tool for a political campaign.

But the new approach doesn’t end there – the 11 different email variations sent last May were not just tailored for each voter, they were also most likely contributing to an ongoing experiment testing the efficacy of various topics and phrases.

After all, what good is it to identify likely or possible voters if you can’t also identify the most effective means of persuading voters, encouraging participation and donations, and boosting turnout among your likely supporters.

“Campaigns now have tools to confidently assess cause and effect through the use of field experiments,” says Issenberg. “Our understanding of what works and what doesn’t used to be reliant almost entirely on who is the best storyteller. Because there is so much going on in a campaign in a given moment that we in the press or the public have trouble understanding what was moving votes. The use of field experiments, which are basically drug trials but which are using voters as guinea pigs, has given campaigns tools to actually measure movement in voters’ opinions and behaviour in the real world.”