Response to "Revisiting ISO 14000 diffusion: A new "Look" at the drivers of certification"

Abstract

In Corbett and Kirsch (2001), we used a simple regression in an exploratory investigation of drivers of global diffusion of ISO 14000 certification. We found that ISO 9000 certification levels, environmental treaties ratified, and exports as a proportion of GDP were the main significant variables, where the environmental measure may be moderated by GDP per capita. In his replication study, Vastag (2004, in this issue) analyzes the same data using more visual techniques, specifically regression trees, and finds support for the significance of ISO 9000 certification levels and environmental treaties ratified, but not for export-propensity. Vastag raises a number of relevant methodological issues, to which we add some perspectives here.