When Weber Shandwick learned late last year that Interpublic Group of Cos.' sibling Mediabrands had constructed a system that allowed other shops in the holding company to access its tools and data, the PR giant wanted in.

Now Weber Shandwick can access data down to ZIP codes and geography, and is using Mediabrands' data to identify and target audiences, as well as study how exposure to earned and social-content prompts behavior like buying habits.

Like Interpublic, most holding companies began centralizing their disparate data resources last year so their agencies could access behavioral data for a small fee. This year, those systems are live, and PR agencies -- arguably the most data-deprived of the bunch -- are diving in.

These shops have typically operated in the earned-media space and struggled to tie their work to real results like sales, but the new data is allowing them to better track their efforts, find opportunities to boost social content and even get into paid media. For parent companies, it offers funding to support expensive technology investments for data management and analysis.

"We've seen the data sets our sister shops have access to," said Gail Heimann, president of Weber Shandwick. "Being successful requires deep knowledge of content-consumption behaviors."

Earlier this year, PR agency Cohn & Wolfe joined other WPP companies as a member of the Data Alliance -- the holding company's new central group that brokers deals and partnerships between its member shops and its data-rich operations like research giant Kantar and digital-buying group Xaxis. The agency can now use aggregated consumer data from Xaxis to see who is sharing BuzzFeed links on Facebook and insert branded content into those conversations, said Chad Latz, president-global digital lead at Cohn & Wolfe.

"We're gaining access to real-time data streams [that show] how [consumers] are navigating content and experiences online," he said. "We're using data to deepen consumer profiles."

He said the shop is accessing cookie data for a client he declined to name to analyze consumers' affinities for brands and how they engage with content online. Cohn & Wolfe will use that data, as well as information pointing to purchasing behavior, to guide content strategy and distribution.

"PR firms have a legacy where they've had trouble representing the total value [of their capabilities] against more-measurable media and paid media," said Nick Nyhan, CEO of WPP's Kantar, who leads the Data Alliance. "With the advent of social media, data sets are almost uniquely suited for PR and the earned-media space. It helps to quantify what was harder to quantify before."

Omnicom PR shop Ketchum is using data to get into the paid-media space and, like most of the large PR shops, to better target audiences across paid, owned and earned channels. The shop is forming a group of dedicated planners and buyers; inking new contracts with ad-tech companies like social-buying group Kenshoo; and investing in software that automates the targeted-buying process online. Called Agile Amplification, Ketchum's new group benefits from master contracts between ad-tech vendors and parent Omnicom, as well as Annalect, the holding-company's central digital-media and data operation that lives within the media-agency network.

"We can get social data into a cloud-based environment where it can be scrubbed, cleansed and transformed really quickly," said Scott Hagedorn, CEO of Annalect. "[Agencies] will have access to what we call the Agile Data Warehouse, a repository for all our data across the holding company." The information and tools these groups offer aren't free. For example, Cohn & Wolf might pay fees to sources from which it gathers data and insights. With the help of the alliance, it's also investing in training for the shop's 1,100 employees and paying a small fee to be part of the Data Alliance, which organizes internal events, presentations and consultative services for members.

"There is a cost model in place, but it's basically a subsidy to offset hard costs," said Keith Camoosa, exec VP-managing director of research and analytics for Mediabrands' digital group Magna Global. "Our framework with Weber is to open up a pipe into the database and have it directly connect to Weber. [Our] group keeps rates down since it procures at scale."

Shops like Weber are willing to spend the money on access because they believe clients will also pay more for better targeting and proof points. Early tests "are showing that people who had exposure to our content behaved in a different way," said Weber Shandwick Exec VP-Measurement Allyson Hugley.

"It's an investment in what clients are saying they need," said Paul Rand, Ketchum chief digital officer and CEO of Ketchum subsidiary Zocalo Group. "They'll pay for it, but we [first] have to build and hire."