Testing causal structure in the biogeography of avian extinctions on oceanic islands

In their recent comment in this journal, T. M. Blackburn and colleagues called into question the use of standardized partial regression modelling (also called path analysis and structural equation modelling) when null expectations for regression coefficients are not zero. Here, we answer their critique by showing how randomization can be used to illuminate and interpret causal modelling in analyses that have non?zero expectations. Causal modelling is a powerful tool that can yield novel insights in biogeography when properly interpreted.