Exploring the use of our methods has highlighted the importance of defining the boundaries of the system being studied and attending to features of underlying systems that afford causal processes. We note that our limited application of our methods cannot confirm that all the implementation actions were necessary, though our examination of L shows how this might be shown by broader study. We note that, while our methods may seem daunting, they’re no more detailed than statistical methods used in quantitative research and have practical advantages in supplying more detailed qualitative evaluations. They may also be used for ex ante appraisal. We stress the importance of understanding mechanisms in practical research and note that actual research involves back-and-forth between evidence and theories of change, even though we detail the former first in our evaluation. We note the value of such evaluations in combatting problems such as, relevantly, costly failed reforms.

Very few, if any, causal processes are self-standing – rather, they depend on features of ‘underlying systems’: sufficiently stable physical, socio-economic, legal and cultural conditions that afford such processes (‘mechanisms’ in some New Mechanists’ terms). The underlying system is whatever it is in the world that affords the causal process – a structure exhibiting sufficient stability that affords the causal activities that occur within the process and the principles that govern them. This is illustrated by Rube Goldberg machines and examples from biochemistry, economics and deskilling in child protection. Underlying systems are helpfully understood through assessing their components and features, and the affordances associated with them, with the boundaries of the underlying system considered pragmatically.