大数据能否左右选举结果？

    There's a powerful vignette in Sasha Issenberg's The Victory Lab in which political consultant Alexander Gage presents his new data targeting system to Mitt Romney's 2002 gubernatorial campaign.

    Gage has combined consumer records with political voting history to identify potential Romney supporters among nontraditional Republican voting blocks. Gage sees his work as revolutionary -- a first in politics, and potentially a first anywhere. Yet just as he completes his presentation, Romney's deputy campaign manager Alex Dunn raises his hand and deadpans, "You mean you don't do this in politics."

    Dunn's surprise was not out of place in 2001. And while much has changed since then, politics remains an analog art in many ways. The Victory Lab charts the recent history of political data mining designed to identify persuadable voters and swing elections.

    Politico has called Issenberg's book "Moneyball for politics." There are obvious parallels between political operatives like Gage and the protagonist of Moneyball, Oakland Athletics general manager Billy Beane. Both pioneered data-centric techniques that gave their respective organizations a leg up over the competition.

    Yet in his 14 years as GM, Billy Beane has yet to make it to the World Series. By contrast, the work of Gage and other data-mining political consultants has translated directly into electoral success. These operatives may not have singlehandedly won the past two presidential elections, but the side that had the most advanced data-driven mobilization efforts went a perfect 2-0.

    The George W. Bush campaign's sophisticated data mining helped the president win reelection in 2004. Four years later, Barack Obama defeated John McCain in part because the Obama campaign outclassed McCain's operatives on the data front.

    Issenberg seems to have interviewed everyone who's anyone in the field of political statistics, but his subject matter doesn't necessarily lend itself to prose. Numbers have power, but too many of them can addle rather than inform. After reading the book, you'll probably remember the outcome of a few experiments, but be stuck scouring your brain for the results of the rest. Readers are advised to keep a pen and pencil handy when reading The Victory Lab, so they can jot down key stats.

    Yet Issenberg's material is sufficiently gripping that you'll want to keep turning the pages, even if it means deciphering the results of yet another randomized trial. For example, micro-targeting efforts on behalf of Senator Michael Bennett (D-Colo.)'s 2010 Senate reelection campaign likely spurred 25,000 additional Bennett votes. That might not seem like a big number, until you consider that the race was decided by 15,000 votes.

    Issenberg avoids sweeping predictions about the future of political data mining. That's probably wise, given that political professionals tend to define the future as Election Day. Campaigns at their simplest are a one-day snapshot of personal preference. The Victory Lab reminds us, however, that every individual choice is the result of a thousand factors, many of them subject to manipulation by political operatives.