The famous John Wannamaker quote that “half of the money I spend on advertising is wasted; I just don’t know which half,” seems pretty apropos in relation to last week’s US elections. Indeed, Las Vegas billionaire Sheldon Adelson, who spent an estimated $53 million supporting eight Republican candidates, can only dream of a success rate comparable to Wannamaker’s—only one of those eight candidates emerged victorious. Meanwhile, the former chief of staff to President George W Bush, Karl Rove, put together an organization that raised and spent more than $1 billion. According to this Business Week report, Rove’s groups “backed unsuccessful Republican presidential contender Mitt Romney with $127 million on more than 82,000 television spots, according to Kantar Media’s CMAG, an ad tracker based in New York. Down the ballot, 10 of the 12 Senate candidates and four of the nine House candidates the Rove groups supported also lost their races.” I dare say advertising professionals would argue that spending so much on television spots was important, even though it didn’t translate into victory: that the ad campaigns on either side of the political divide merely canceled each other out, that if Romney and other Republican candidates had not spent so much on advertising, the vote would have been nowhere near as close as it was. And for sure, there is some evidence that the Obama campaign’s early advertising in Ohio—much of it while Romney was still focused on the Republican primary, and much of it focused on Romney’s opposition to the auto industry bailout—helped shape perceptions of the GOP candidate in that critical state. “Before they even decided who the [primary] winner was, the Obama campaign had already decided it was Mitt Romney, and here in Ohio they spent millions and millions to make sure they defined who Romney was,” says Lucas County Republican Party chairman Jon Stainbrook. “They portrayed him as an out-of-touch billionaire, and that resonated until the first debate.” Romney was unable to shift those perceptions when he began his ad campaign, even though he outspent his opponent by a significant margin. But if there is an argument to be made that a substantial investment in paid advertising is still necessary to mount an effective election campaign, there can surely no longer be any argument with the suggestion that grassroots marketing is more critical to success—and a better investment—than a giant ad buy. This fascinating Time magazine analysis looks at just how sophisticated the Obama campaign was when it came to the use of big data, in both fundraising (“a large portion of the cash raised online came through an intricate, metric-driven e-mail campaign in which dozens of fundraising appeals went out each day”) and get-out-the-vote efforts (“the analytics team used four streams of polling data to build a detailed picture of voters in key states”). The Obama campaign also used social media more effectively as this article in The Hill explains: “The campaign also leveraged a variety of social-media tools to target various demographics. It used the online bulletin board-style tool Pinterest to reach out to women and the blogging site Tumblr to target young voters.” Throw in an enthusiastic army of volunteers on the ground, described in this Slate piece, and it is clear that the Obama “ground game” was much more effective at turning out voters than its Romney counterpart. (For an interesting analysis of the problems Romney had with his own big-data, get-out-the-vote effort, known as ORCA, this NPR report provides an overview.) There is a clear lesson for marketers and corporate communicators in all of this. Advertising may still be a necessary part of any campaign, but the combination of big data, social media and a strong, grassroots movement of brand advocates is even more powerful. And that has to be good news for public relations people, if they can integrate big data into their existing skill set and develop the kind of credible, authentic messaging that engages consumers and others stakeholders and motivates brand advocates.