Over the last couple of months, John McCain has launched at least a dozen automated phone campaigns that question Barack Obama's alleged ties to terrorists, among other charges. McCain, who was famously targeted by ugly robo-calls in the 2000 presidential primary, defends his effort as "totally accurate." Several Republicans have criticized the calls. Even Sarah Palin says she doesn't much like them. The Obama campaign has scolded McCain to stop the phone campaign; Obama has even launched his own robo-calls to denounce McCain's robo-calls.
With all this Sturm und Drang, you might think that automated phone calls will make a difference in the presidential race. They won't. Robo-calls are the pyrotechnics of politics: They create a big disturbance, but they don't have a prolonged effect. Numerous studies of robo-call campaigns show that they're ineffective both as tools of mobilization and persuasion—they don't convince voters to go to the polls (or to stay away), and they don't change people's minds about which way to vote. So why do campaigns run robo-calls? Because they're cheap and easy. Telemarketing firms charge politicians between 2 and 5 cents per completed robo-call; that's as low as $20,000 to reach 1 million voters right in their homes.
Compared with TV advertising, door-to-door canvassing, and mega-rallies, automated phone calls are seductive because they harness modern telecommunications technology in the service of political persuasion. That being said, it's Obama's campaign, not McCain's, that has hit upon the cheapest effective way of contacting voters via the phone: text messaging. During the last two years, Obama has collected hundreds of thousands, if not millions, of cell phone numbers from loyal supporters and new registrants. Now his campaign is sending out text messages to people across the country—the texts remind people to register to vote, to go to the polls, and to organize others on behalf of the campaign.
On the surface, these texts don't seem that different from robo-calls—they're both automated messages and both easy to ignore. But for reasons that aren't completely understood, text messaging is different: We pay attention to short messages that pop up on our phones.
These conclusions arise out of work by Donald Green and Alan Gerber, two political scientists at Yale whose book, Get Out the Vote: How To Increase Voter Turnout,is considered the bible of voter mobilization efforts. Green and Gerber are the product of a wave of empiricism that has washed over political science during the past decade. Rather than merely theorizing about how campaigns might get people to vote, Green, Gerber, and their colleagues favor randomized field experiments to test how different techniques work during real elections. Their method has much in common with double-blind pharmaceutical studies: With the cooperation of political campaigns (often at the state and local level), researchers randomly divide voters into two categories, a treatment group and a control group. They subject the treatment group to a given tactic—robo-calls, e-mail, direct mail, door-to-door canvassing, etc. Then they use statistical analysis to determine whether voters in the treatment group behaved differently from voters in the control group.
Political scientists have run dozens of such studies during the past few years, and the work has led to what you might call the central tenet of voter mobilization: Personal appeals work better than impersonal ones. Having campaign volunteers visit voters door-to-door is the "gold standard" of voter mobilization efforts, Green and Gerber write. On average, the tactic produces one vote for every 14 people contacted. The next-most-effective way to reach voters is to have live, human volunteers call them on the phone to chat: This tactic produces one new vote for every 38 people contacted. Other efforts are nearly worthless. Paying human telemarketers to call voters produces one vote for every 180 people contacted. Sending people nonpartisan get-out-the-vote mailers will yield one vote per 200 contacts. (A partisan mailer is even less effective.)
Meanwhile, pinning leaflets to doors, sending people e-mail, and running robo-calls produced no discernible effect on the electorate. Green and Gerber cite many robo-call studies, but the most definitive is a test they ran during the 2006 Republican primary in Texas. Gov. Rick Perry recorded a call praising a state Supreme Court candidate as a true conservative. The robo-call was "microtargeted" to go out only to Perry supporters—people who'd be most open to his message. But as Green and Gerber show, Perry supporters who received the call reacted no differently from those who'd been kept off the list. They were no more likely to vote, nor, if they voted, to vote for Perry's candidate.
These findings create an obvious difficulty for campaigns: It's expensive and time-consuming to run the kind of personal mobilization efforts that science shows work best. Green and Gerber estimate that a door-canvassing operation costs $16 per hour, with six voters contacted each hour; if you convince one of every 14 voters you canvass, you're paying $29 for each new voter. A volunteer phone bank operation will run you even more—$38 per acquired voter. This is the wondrous thing about text-messaging: Studies show that text-based get-out-the-vote appeals win one voter for every 25 people contacted. That's nearly as effective as door-canvassing, but it's much, much cheaper. Text messages cost about 6 cents per contact—only $1.50 per new voter.