There are three players in the social impact bond game:GovernmentService ProvidersImpact InvestorsIn a social impact bond, impact investors provide the working capital for that service provider to be able to solve the problem.For ideas to be considered feasible, they must meet three basic criteria:Can it produce measurable outcomes?Can it produce outcomes in a short timeframe?Is there previous evidence of success?Four reasons why one would seek an impact bond versus a more traditional type of funding:It makes money more effective by tying funding to measurable results.It allows service providers to better adapt to change.It incentivizes better programs making it attractive and profitable for service providers to improve the programs they already have.It focuses the private sector on social issues by creating an investment opportunity that includes a financial return.Currently there are 151 active social impact bonds in use by 29 countries.Active social impact bonds mentioned:Multinational bank gives a girl's education nonprofit from India enough funds to scale their program to three new villages.Large education philanthropy paying back the initial investment after three years based on the number of girls who've been enrolled in school and their learning gains.A set of impact investors invest in improving the services of diabetes management clinics to work with specific high-risk population.Brookings Global Economy & Government:48 social impact bonds in employment52 social impact bonds in social welfare21 social impact bonds in health17 social impact bonds in education10 social impact bonds in criminal justice3 social impact bonds in environment3 social impact bonds in agricultureAverage social impact bond duration = 50 monthsAverage upfront capital = $3.5mSocial impact capital outlay = $420m