This digital document is a journal article from Ecological Economics, published by Elsevier in 2006. The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser.Description: We develop two slacks-based efficiency measures for modeling environmental performance on the basis of environmental DEA technology. Of the two measures, one is a composite index with a higher discriminating power for modeling economic-environmental performance, and the other can be used to estimate the impacts of environmental regulations. We apply the proposed measures to model the CO"2 emissions of 30 OECD countries from 1998 to 2002 and present the results obtained.