A form of results-based contracting, Social Impact Bonds, is gaining popularity and there are increasing amounts of literature around this.
The Social Finance UK website defines Social Impact Bonds as, “a form of outcomes-based contract in which public sector commissioners commit to pay for significant improvement in social outcomes (such as a reduction in offending rates, or in the number of people being admitted to hospital) for a defined population.” There is more information about their work in specific sectors, including Criminal Justice, Health and Ageing, Drug Rehabilitation and other.
A good article explaining Development Impact Bonds and giving three advantages of this way of working can be found on the Center for Global Development website: Why Development Impact Bonds?
Also, find a summary of the Peterborough Prison Pilot Social Impact Bond for working with short-sentence prisoners.