ALL proceeds of this book go directly to the Howard League for Penal Reform. Payment by results is a controversial new approach to commissioning which tends to polarise opinions. This, to a large degree, is because it doesn’t yet have an established evidence base and many of the current pilot schemes described as PbR seem to have relatively little in common in terms of their design principles. This ebook is my attempt to set out those principles and suggest that if we took our time in building clearer PbR models, we’d have a much better idea about whether payment by results could revolutionise the commissioning of public services, or whether it is merely just a way of siphoning off profits to the private sector.