Jaffe and Palmer (1997) present three distinct variants of the so-called Porter Hypothesis. The weak version of the hypothesis posits that environmental regulation will stimulate certain kinds of environmental innovations. The narrow version of the hypothesis asserts that flexible environmental...

It is generally recognized that firms face both internal and external pressure to improve their environmental performance. However, few studies have attempted to delineate the importance of those various sources of pressure as firms' managers themselves perceive them. In this study, we show that...