In the 2012 presidential postmortems, Democrats claimed that an army of computer engineers, mathematicians and social scientists created a huge data advantage over Republicans that helped President Obama win re-election. There's truth in that.
Two aspects of this data gap stand out. The first is microtargeting. This means compiling and using hundreds of pieces of information about each voter that—combined with survey research—can help campaigns predict how likely a person is to vote, how persuadable they are, what issues matter to them, and what arguments they find persuasive.
Republicans historically did this better, but they microtarget once in the late spring or early summer, hoping this snapshot will remain stable through election day. Team Obama integrated polling data into their voter file and frequently did large surveys with short questionnaires. This steady flow of attitudinal information gave them a dynamic view of the electorate's constantly changing opinions, and allowed them to constantly update and refine their microtargeting.
The Democrats' second big edge came from Team Obama integrating volunteers, donors and Web visitors into their voter file where they, too, were microtargeted. The social networks and address books of these individuals also were swept, with their contacts tagged on the voter file.
This enabled the Obama campaign to contact voters using volunteers who they either knew, or who shared their background and cared about the same issues. Volunteers were armed with messages personally tailored for each voter. This is far more powerful than phone calls or knocking on doors with a general script.
Democrats have developed other digital tools to help volunteers. One application tracked Obama supporters who requested an early ballot to see if they actually voted—possible because most jurisdictions make available lists of early ballots cast. Another told Facebook users which of their friends were Obama target voters and helped these volunteers to work them. Volunteers also could download a "walk list" to tablets or smartphones and report voter responses without going to headquarters.
Donors could also store credit-card information on the Obama website, making repeated gifts possible with one click from any device and generating dramatically more money. The campaign also conducted endless experiments testing the effectiveness of messages for persuasion and fundraising.
Can the GOP catch up? Understanding that today's technology has the shelf life of a banana, Silicon Valley Republicans are working to modernize the GOP's voter file in advance of next year's midterms. They know users want an interactive platform with applications so that any Republican candidate or conservative organization can better identify, persuade and turn out voters.
The information and applications should provide for dynamic microtargeting and at least match the Obama campaign's ability to connect target voters with volunteers they know or whose interests match their own. It should also be possible to update the master voter file in real time from phone banks, door knocks, online activity and other data streams. The platform will use open architecture, so enterprising GOP developers can build additional applications that candidates and campaigns find useful.
There are big challenges—and not just about quickly writing code. The more campaigns rely on social media and personalized messaging, the more people they will need with communications skills, along with more computer scientists, mathematicians and data-analytics experts.
Silicon Valley leans heavily left, giving Democrats a bigger talent pool. But that was also the situation in 2004 when President George W. Bush's campaign created a technology advantage over Democrats. There are enough Republican techies, companies interested in selling services, and even a small group of GOP-leaning social scientists who can run analytics and manage experiments.
In the end, was the Democratic data advantage decisive last November? After all, the data-rich 2012 Obama campaign received 94% of the votes Mr. Obama received in 2008, while the supposedly data-starved Romney campaign got 102% of John McCain's 2008 total. Still, if Team Obama's data edge only marginally improved his standing—say, increased it by two percentage points more than it would have been otherwise—the result pushed Mr. Obama over the top in Florida, Ohio and Virginia. That's 60 electoral votes.
Erasing the GOP's data deficit is no substitute for effective messages and strong candidates. But closing the gap will help Republicans deliver those messages better and put more members of their party in the winners' circle. That, in turn, will affect policy—and with it, the course of the nation.
A version of this article appeared March 21, 2013, on page A13 in the U.S. edition of The Wall Street Journal, with the headline: Closing the GOP's Election Data Deficit, and online at WSJ.com.