Does the complexity of social challenges mean that the oft touted winning attribute of social impact bonds (SIBs), namely measurement, is an empty boast? In his second look at SIBs, James Ronicle continues to scratch his chin.

Social impact bonds are growing in popularity across the globe, but are they ethical? In the first of two articles, James Ronicle reports on an event that brought together 40 researchers to debate the pros and cons.