Australia confiscated 650,000 guns. Murders and suicides plummeted.

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.

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.

Preparing the young for elementary education is a priority to nurture reading and social skills. For 16 years, Tulsa Oklahoma has instituted a state funded preschool, staffed with teachers trained in early education. Tulsa’s Pre-K initiative has shown that their children are more prepared for literacy skills and math; however, maintaining the positive results is a long-term challenge.

Milwaukee County’s mental health system put more resources in expensive emergency care rather than invest in programs that offer continual care. As a result, Milwaukee County identifies nine solutions from other cities that have had success in repairing mental health systems. Solutions include the ending of reliance on emergency care, expand community support programs, change laws, and supportive housing.

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.