Over the last 5 years, substantial progress has been made in the development and use ofenvironmental performance indicators, so that, by and large, the problem of indicatoravailability has shifted to the more intricate problem of indicator suitability. Focusing on theneed to compare companies’ performances, the question today is “how many (and which)indicators are the minimum necessary to provide an approximate yet reasonably robustdescription of the comparative environmental performance of companies”? The resultssuggest that it is possible to provide a reasonably accurate picture of the total diversitycontained in the data (i.e. diversity of firm performance) by using a minimum set of variables.This has obvious implications for management as well as public policy.