Jonathan Greenblatt's recent post from the White House's Center for Social Innovation and Civic Participation is a good summary of the federal government's current approach to pay for success (PFS) aka social impact bonds. The relatively slow rollout of PFS also highlights the challenges of leading from the top for an instrument which is typically built on local service provision.
Building a Smarter, More Efficient Government through “Pay for Success” | The White House
Building a Smarter, More Efficient Government through “Pay for Success” | The White House