World Englishes (WE) research has been invested in getting to grips with the diversity of different Englishes and in making sense of their structural properties. The first research strand led to a proliferation of theoretical models, the second to comparative research relying increasingly on sophisticated statistical modelling. The connection between these research strands is not always as clear as we might wish, and occasionally even rather tenuous. This paper revisits existing models of WEs with a view to their predictive ‘power’ and reviews recent corpus-based studies with respect to the ways that these have tried to operationalise predictions of theoretical models. It uses a mental model to understand exactly why it is apparently so difficult to bring intricate, quantitative modelling of usage data to bear on theoretical modelling.