Cities talk a lot about harnessing big data, but their efforts vary widely. Some, like New York City, Columbus, and Kansas City, Missouri, have emerged as leaders in using data to tackle issues surrounding transportation, inequality, and health, while others like Anchorage, Alaska, are just starting to mine theirs. All would benefit from more guidance; the more experienced cities need to know they're on the right track and the newcomers could use a roadmap of best practices.

That's why Bloomberg Philanthropies is introducing a new certification initiative that aims to set the national standard for how local governments enact evidence-based policies. Think of it as a Good Housekeeping Seal, or LEED certification, but for data-smart cities.

The certification was announced this week at Bloomberg's second annual What Works Cities summit in NYC, part of the organization's efforts to expand their current initiative offering technical assistances to dozens of cities over the past two years.