We offer evidence-role maps detailing the relations between available data and the claims made by the theory of change we have developed for the L pathway. Using these maps, we then evaluate warrant for the causal claim made by each of the steps in the L pathway, establishing what we take to be a strong warrant for each of them and hence our overall account of this pathway and the singular causal claim that the introduction of collaborative case audits contributed to Signs of Safety implementation in M. In doing so, we illustrate our method for establishing warrant for such causal claims.

A ‘thick’ theory of singular causation, incorporating enough detail to allow you to know how to evidence singular causation, is required for empirical investigation of singular causal claims. The term ‘mechanism’ is often employed in describing how a cause produces its effect on any particular occasion. Here we point out that this term is ambiguous between the step-by-step process by which a cause produces an outcome, the underlying conditions that afford causal processes and the causal principles under which causes produce their effects.

This book shows how to warrant claims about causation in a particular place at a particular time, ‘here and now’, ‘there and then’ – ‘singular’ causation. Good warrant matters if your efforts to affect change are to work. But you cannot properly warrant that a relation obtains without understanding what that relation is. To this end, Part 1 offers a set of features that characterise singular causal relations. These make up a ‘thick’ theory of singular causation, offering far more information than the usual ‘thin’ definitions, like those based on counterfactual or probabilistic dependence, difference-making or production. Details about how causal processes work play a central role here. This theory then provides the grounds for, in Part 2, identifying and systemising what kinds of evidence can warrant singular causal claims. Part 3 shows how this account may be used in practice, using examples from child protection.