The Right to Rule by Thumb: A Comment on Epistemology in “A Route Map for Successful Applications of Geographically-Weighted Regression”

Comber et al. provide an important contribution to the future of quantitative geography and Geographical Analysis. The contribution is chiefly in their development of a “GWR Route Map,” a diagram showing the sequence of analytical steps that “successful” specification searches in local modeling tend to follow. Geographically weighted techniques have been rapidly expanding, both in terms of complexity, users, and disciplinary reach. With geographically weighted methods now in so many more analysts' hands, any new rule of thumb will have a major imprint. But, by what right does the thumb rule the analysts? That is, what “counts” as valid knowledge about local models in general? In the following comment, I argue that we probably should use theory, not route maps to decide specifications. But, if we are pressed to build route maps, we sorely need better epistemological foundations for them. I discuss a few previous examples of strongly grounded route maps and offer a few paths to these better grounds as well as two ways to the exit.