Causal equation models are sets of equations showing the functional dependence of effect variables upon cause variables – it is supposed that all individuals in a given population satisfy these equations. We describe ‘situation-specific’ causal equation models (SCEMs) which apply this modelling method (common in social science) to the particular circumstances associated with singular causation. These are taken to represent the range of causal possibilities that occur in these particular circumstances. To construct a SCEM, work backwards step by step from the final outcome, constructing a potential outcomes equation for each stage until the initial cause. The resulting set of equations is the core of the SCEM for this case. We illustrate how such a model may be generated using our example of sugar-sweetened beverage taxation in Barbados. We admit the causal equation models thus generated are complex, but contend this only represents complexity in nature.