Public agencies commissioning social impact bonds or other payment by results programmes want to see some kind of cost benefit analysis. But they might not always be so willing to provide the information an external organisation needs accurately estimate the benefit side. Different commissioners also have different requirements for cashable savings – for some it’s a key driver and for others it’s not a consideration.

I suggest that collecting benefits into the following five categories makes the information for the commissioner much clearer and, for UK commissioners, also explicitly addresses the requirements of the Social Value Act. All estimated amounts should be itemised and if an external applicant is unsure of the savings or benefits to public service agencies, then they should present a best estimate that prompts the commissioner to provide a more accurate figure. The Global Value Exchange is a database of proxy values that will be helpful for this.