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Voter-file targeting is all the rage in the digital political advertising world of late. It was on everyone’s lips at April’s CampaignTech conference, and I’ve heard from online ad networks that don’t provide the service that they’ve been forced to team up with companies that do. Otherwise, they wouldn’t be able to compete in this year’s political advertising market.

As one ad sales rep told me, “It’s all the campaigns are asking for.”

But is it all they should be asking for?

First, let’s define the subject. Several digital advertising companies, including CampaignGrid on the right and DSPolitical and Precision Network on the left, now promise campaigns the ability to target online ads directly to people on an outreach list provided by the campaign. Typically, campaigns and their consultants create the list based on a voter file for their districts, frequently attempting to target their base voters with recruiting and turnout messages or swing voters with persuasion messages.

Here’s how it works: The campaign builds a contact list by combining a targeting model and the voter file, working with a vendor that has relationships with consumer online ad networks and/or individual content sites. The vendor matches the contact list with databases compiled by the ad networks as they track Internet users via digital “cookies” placed on their computers by websites they visit.

Note that these cookies are part of the same technology that “remembers” you when you return to a site which you’ve visited before, and which lets The New York Times cut you off when you try to read more than 10 articles a month.

Once a campaign’s voter file is cross-referenced with an ad network’s cookie database, the network can start sending online display (banner or rich media) ads to the universe of people the campaign wants to reach, typically using a wide variety of websites to deliver the ads. To get even more specific, the list can be cross-referenced with demographic information the ad networks and content sites compile about the people they track.

Need to reach married women between the ages of 25 and 40 in Ohio’s 10th Congressional District? Cookie-based voter-file targeting will let you do it, at least in theory.

Here’s the trick—every level of targeting involves a certain risk of inaccuracy. For instance, a vendor might be able to match 60 percent or 80 percent of your voter file with the appropriate web cookies, so note that right away you’re not reaching everyone on your target list. Plus, you’re probably paying to reach at least some people who were improperly matched. And we’re still only talking about targeting based on information in the voter file, such as voting history or party affiliation.

Demographic targeting potentially adds uncertainty, since every layer of filtering involves some level of imprecision. For instance, a recent comScore survey of online ad targeting by 12 consumer brands found that “campaigns with 3 variables (e.g. women + 25-54 years old + with children under 18 in the home) delivered impressions to the target an average of just 11% of the time. By comparison, those with 2 variables reached their intended audience an average of 48% of the time, while those with 1 variable delivered impressions to the target 70% of the time.”

These results have serious implications for the technique’s practical Return On Investment.

So what should a campaign do? I’d argue that cookie-targeted ads are a powerful tool but that they shouldn’t be the only online advertising a campaign runs. Fortunately, vendors agree.

DSPolitical’s Jim Walsh says “voter-file targeting is the best innovation I’ve seen in the political technology space since CRMs came along,” but that he would “never suggest to a campaign that they spend their entire online advertising budget on it.”

Likewise, Precision’s Tim Lim calls cookie targeting “a lot more efficient than just wildly guessing at the target audience,” which he believes many online advertising campaigns have done in the past. But he stresses the need to combine it with other tools, making clear it “isn’t the Holy Grail” of online politics, but “it’s an integral part of any persuasion program, and I think it will prove to be integral for acquisition programs as well.”

Quality counts, with Walsh noting that advertising effectiveness comes from “good data, a good cookie pool and a distribution network with a broad reach.” CampaignGrid’s Jordan Lieberman says, “The race to the top is on match rates,” and suggests that campaigns pay close attention to who’s actually criticizing the practice: “People who are pushing back on cookie targeting are the ones who don’t know how to do it.”

As in so much of digital politics, integration is key. For instance, a campaign might aim cookie-targeted ads at its base voters or identified swing voters, while also running geotargeted Facebook Ads to hit particular demographics in the district and Google Ads on key search terms (the candidates’ names, for instance). Some campaigns may even go outside their own immediate areas to place ads on major state-level newspapers or political blogs, trying to catch influential voices and potential donors who don’t live in their districts.

By combining advertising channels, a campaign can target messages as precisely as possible while also avoiding leaving votes on the table. As Lim says, “employing all of these methods in a coordinated fashion, you’re going to get much better results.”

So think of cookie-based voter file targeted ads as an important part of a balanced breakfast—a key component in the mix of digital tools a campaign uses to recruit and persuade, but not a panacea.

Colin Delany is founder and editor of the award-winning A contributor to Campaigns & Elections, Delany writes C&E's Technology Bytes section. Send him a pitch at