Aim Island isolation is measured in many ways. We seek to determine what the underlying latent factors characterising these measures are, in order to understand how they mechanistically drive island biogeographic patterns and in order to recommend the most parsimonious measures. We then test the discriminatory power of the identified components against hypotheses generated from the biogeographic patterns of invasive rats. Taxon mammals Location The 890 offshore islands (≥ 1 hectare area) of the New...