Social and environmental systems are as complex as obesity and as unresponsive to the 'cause and effect' model of government intervention. In the early days of benign government the relationship between a problem and its cause was often much easier to identify - and probably still is for the afflictions of the poorest members of society. In such cases provision of, for example, basic infrastructure, education and housing was - and is - an almost unambiguous good. But society today is as complex as the human body. Identifying a single cause of, for instance, obesity, or baldness, cancer etc, is unlikely to be fruitful. Sadly, that is the way governments operate: indeed it is the way our individual thinking operates. But for complex problems more subtle ways of finding solutions are necessary. They require diverse approaches, and ones that adapt over time. Climate change and nuclear proliferation, to take a couple of urgent challenges, are at least as complex as obesity, and are going to be at least as unresponsive to the usual approach.
What seems abundantly clear is that banging on at entire populations to eat less and exercise more has been an utter failure in terms of reducing levels of obesity.
The Social Policy Bond approach is to stipulate the targeted goal: a stable climate, or nuclear peace, and reward people for achieving it, however they do so. It would be up to investors in the bonds to research, investigate, and implement different approaches. They would be highly motivated to terminate their unsuccessful projects (something that government rarely does) and to adapt and replicate their successes. I think the bonds offer a better solution to complex social and environmental problems than the current, cause and effect, model.