A growing number of people are interested in investing in companies that perform well environmentally as well as economically. Unfortunately, measuring environmental performance is not as straightforward as calculating a simple financial return on investment. Developing a yardstick for environmental performance is inherently fraught, forcing evaluators to reduce all of the complex dimensions of sustainability, greenhouse gas emissions, water consumption, biodiversity impacts and other factors into a single value. Unsurprisingly, there is no consensus on the "right" approach and a proliferation of methodologies has caused confusion and eroded confidence among potential investors. When researchers at UCLA and McGill University conducted an evaluation that disentangled the different dimensions of environmental performance, they found troubling results.
... "Triangulating Environmental Performance: What Do Corporate Social Responsibility Ratings Really Capture?" by Magali A. Delmas, Dror Etzion, and Nicholas Nairn-Birch in Academy of Management Perspectives, August 2013
Read full article: Huffington Post, March 1, 2014