Spencer Platt/Getty Images - Former New York Mayor Michael Bloomberg

If you call the fire department in Mesa, Ariz., chances are it won’t respond with a big ladder truck. That’s because you probably don’t need one. Odds are that what you really need is medical attention, and if you do, the department will get it to you – in the form of a smaller truck staffed by a firefighter and a nurse’s assistant from a local hospital.

The ladder trucks still roll out to actual fires, but saving them for that purpose and not sending a fully staffed one to every fire call that comes in have saved the city money and improved the quality of care for the people it serves. Those improvements are the result of a deep data analysis the city conducted several years ago, which found that 80 percent of its fire calls were actually medical issues.

Cities across the country would love to emulate that formula: better service for less money. But at a time when data-driven government effectiveness research is having a moment in Washington – most recently, in a bill introduced last week by Sen. Patty Murray (D-Wash.) and Rep. Paul Ryan (R-Wis.) – most local governments are just waking up to its possibilities.

Bloomberg Philanthropies, the charitable arm of former New York City mayor Michael R. Bloomberg, is making a big bet that it can accelerate that process. It will announce on Monday that it is spending $42 million to create the What Works Cities Initiative, which is aimed at helping 100 mid-size cities make better use of data and evidence in their policymaking.

Cities with between 100,000 and 1 million residents will be eligible to apply for help from the program. The money will fund work from several partners, including Results for America, the new Center for Government Excellence at Johns Hopkins University and Harvard University’s Government Performance Lab, all of which will work with the cities selected to participate.

“There’s very little data on the use of data and evidence in local governments,” said James Anderson, a former Bloomberg mayoral aide who leads the government innovation program for Bloomberg Philanthropies. “Mayors are just hungry for tools and resources that help them use data more effectively. What we’ve found is there’s a gap” between what they’d like to do and what they can do.

Driving that hunger is budget math: Local governments around the country cut budgets to cope with the Great Recession, and they’ve largely kept feeling a squeeze through the not-blistering recovery that has followed.

“I don’t know of any government that’s not strapped financially right now,” said Greg Fischer, the mayor of Louisville, Ky., who recently hosted a gathering of civic leaders to discuss data opportunities, “so the question is, how do you do more with less?”

Louisville has put data analysis to work in simple and complicated ways. It dug into restaurant inspection data to figure out why 11 percent of the city’s establishments weren’t being inspected on time. From what they learned, they cut that rate to 0.1 percent.

To better understand incidents of asthma in their town, city officials outfitted 400 inhalers with GPS tracking devices. They mapped where those inhalers were used around town and collected information on time of day, temperature and other external factors that might cause asthma attacks, in hopes that the city might be able to do something to reduce them – say, change traffic patterns or plant more trees.

In Mesa, the firefighting analysis pushed the city to buck convention on how to run a fire department - sending full trucks on every call “was the wrong mode,” John Giles, Mesa’s mayor, said, “but it’s the model that everybody in the country follows” – and eventually to teach other cities how they could reorient their departments, too.

The What Works Cities Initiative hopes to fuel that kind of best-practice sharing. The Johns Hopkins team, for example, will assess cities’ data capabilities – including open data programs that enlist residents to help solve problems – and push cities to share their tools and practices with one another.

“This isn’t just a funding network to get resources into cities,” said Beth Blauer, the executive director of the Hopkins center. “It’s actually a support network.”

Even the pioneers of local-government data initiatives have a lot more they could do, said Giles, the Mesa mayor.  “We’re excited to learn from other cities,” he said, and “just steal good ideas from other people.”