By Tim Higgins, Bloomberg News (TNS)

WASHINGTON — When Scott Tranter, a Washington political strategy adviser, wants to figure out which TV shows Republican voters are watching, he calls Rentrak, a company that uses information pulled from set-top cable and satellite boxes to track viewing habits. Rentrak’s data help Tranter determine exactly where candidates can get the most value for their ad dollars. Rather than advising campaigns to spend $3,000 on prime-time broadcast slots in Des Moines, he tells them to buy airtime during reruns of “Law & Order” on TNT, at a fraction of the cost.

It’s a strategy devised and perfected by former Barack Obama campaign staffer Carol Davidsen, who joined Rentrak in January to oversee political analytics. “My job isn’t to target TV, my job is to figure out that you’re a vote I care about, and what do you do with your time all day long,” says Tranter, whose firm, Optimus, does work for Marco Rubio’s presidential campaign, according to federal election records. “Carol’s very good at piecing all of these different technologies together.”

By hiring Davidsen, Rentrak has solidified its hold on the data driving political ad spending for the 2016 campaign.

Incorporated in 1977, the company originally tracked movie rental inventories, then reinvented itself as a monitoring service for box-office sales. As people began watching movies on cable and on demand, Rentrak developed relationships with service providers to get viewership data it sold to movie studios and advertisers.

On Sept. 29, the company announced it would merge with ComScore, a leader in tracking digital media consumption, in a deal valued at more than $800 million. The merger could allow the combined company to track voters across all their screens. “It’s going to be a good catalyst for companies and advertisers to think more along these lines,” says Brent McGoldrick, chief executive officer of Deep Root Analytics. One of Deep Root’s founders, Alex Lundry, is now head of data analytics for Jeb Bush’s campaign.

Near her desk, Davidsen keeps small maps of the swing states that will be most important in deciding the 2016 presidential election. As the director of integration and media targeting for Obama’s 2012 campaign, she created a tool known as “the Optimizer.” It not only used Rentrak numbers to spit out information on what the likeliest voters were watching but also told the campaign’s media buyers where they could reach the most voters for the lowest price.

Before the Optimizer, the campaign — like most of its predecessors — bought airtime during local news and prime-time broadcasts on the theory that those shows reached the most people. Davidsen’s analysis prompted the campaign’s ad buyers to triple their investment in cable ads, a strategy that made the spots 10 percent to 20 percent more effective, in the campaign’s estimation. The results brought as quick and fundamental a shift as Richard Nixon’s dour appearance in his 1960 presidential debate against John F. Kennedy, Davidsen argues. “After Kennedy, everyone got face powder,” she says. “You didn’t debate whether you were going to powder your face before you went on TV. This question was answered.”

In the 2014 midterms, ad buyers for Republican candidates boosted the number of political commercials on local cable by almost 75 percent over the 2010 midterms, according to NCC Media, which sells local ad space for most cable carriers. Channels such as HGTV, FX and the Food Network were suddenly inundated with campaign messages. “I definitely attribute that to better analytics behind TV advertising,” says Timothy Kay, director of political strategy at NCC. “Part of what’s great about the Rentrak data is that it’s given ratings to networks that we haven’t traditionally seen ratings on because of the small sample sizes that are shown by other media survey companies.”

Nielsen and other companies have also developed ways to track audiences across television and the Web. Smaller companies such as Rovi and FourthWall Media are also getting into the tracking business. But Rentrak has a unique advantage: its access to viewer data from markets across the country. By the end of the year, it expects to track about a fifth of U.S. TV viewing households.

CEO Bill Livek is betting the company’s investment in political advertising will pay off beyond the 2016 election. Businesses are trying to mimic the microtargeting techniques developed by political operatives, and Livek expects they’ll hire people who have relationships with Rentrak. “The smartest minds in America, and I mean that literally, work on these political campaigns,” he says. “Once the election is done they’ve got to get real work, and they end up working at some of the major brands.”

With a team of eight, Davidsen is trying to solve one of the problems that bedeviled her when she was on the campaign side in 2012: how to make sure the same people don’t see a candidate’s ads too many times. Even with its sophisticated analytics, the Obama campaign ultimately realized it was bombarding 6 percent of households in Ohio with more than 60 ads a week.

“That was not the desired intent,” Davidsen says, noting research that suggests voters can be provoked into voting against a candidate if they’re annoyed by seeing too many of the same TV ads. She says ad blitzes can bedevil better-funded campaigns, like Hillary Clinton’s or Bush’s. “The Hillary campaign’s problem is not going to be the lack of budget,” she says. “It’s going to be avoiding these 60 exposures.”

Playing with information goes back to childhood for Davidsen, who as a girl loved organizing her box of crayons more than coloring with them. “I just would ask questions of the crayon box, then organize the crayons to the answers to the questions. What are the feminine colors vs. the masculine colors? What are the citrusy colors?” she recalls. “I have a natural inclination to sort.”

Photo: Marco Rubio is one presidential candidate who is using firms that follow web users’ interests in order to target them for ads for him. REUTERS/Andrew Kelly