What if gun owners had to pass a test? Czech Republic offers an answer.

Can we improve the methods we use to teach math in schools — so that everyone develops proficiency? A grade-school math program is changing how children learn based on the assumption that all children can achieve a high level of understanding.

Colombia has attempted to decrease murder and homicide rates by setting up curfews for teenagers, forcing bars to close earlier in the evening, and creating gun laws to prevent the carrying of weapons. As a result of this epidemiological, data-driven approach, along with other governmental factors, the homicide rate has decreased significantly in most of the cities in which it was implemented.

The pressure is on for the federal government to spend tax money more wisely. Evidence-based policy making is gaining in popularity as a way for the government to spend tax money wisely. While not quite as flashy or exciting as past ways, this has a proven track record of positive impact.

Amidst a world struggling with smart ways to confront climate change, Hawaii's 2050 Plan for sustainability is working to be a model for the rest of the world. So far, it is on it's way to being a leader in solar energy, with Honolulu having the most "solar panels per capita than any other North American city," and the state is working to produce more food locally, as well.

Cities save money and help kids by connecting them with diploma programs. In Washington, iGrad is helping students do just this – and seeing results.

Crime is a result of many underlying social issues, but Crime Lab, a research organization with branches in New York and Chicago, is studying which simple solutions will have the most impact in their city. Cost-effective efforts such as tutoring combined with cognitive behavioral therapy have proven to be successful.

As Vermont struggles to create legislation regulating school district management and financial efficiency, the state looks to models in Maine and New Hampshire for guidance. In Maine, school districts have tried to save money and resources through consolidation; in New Hampshire, officials have reworked the way schooling is financed altogether.

A program in Philadelphia is pioneering new ways to treat the urban wounded. By seeing it as PTSD, and not pointing fingers, the city is using mental health tools to decrease violence and heal communities.

Colorado causes a large decline in teen pregnancy and abortions by implementing free, long-term birth control to prevent pregnancy. While demonstrating massive success, its continuity is in the air considering the ongoing fight over health insurance at the federal level.

The California prison system is overwhelmed after adopting tough-on-crime laws with no improvement. New York adopted more tolerant policies and has decreased the state's crime rate and its prison population.