Ecological Risk Assessments (ERA) quantitatively or qualitatively estimate the potential risks or actual impacts of environmental stressors, such as toxic chemicals or habitat alterations, on biota (excluding humans). Many regulatory agencies in the U.S. have begun to require ERAs to be conducted at Superfund sites. However, these agencies provide limited guidance on the necessary scope of risk analysis effort and the quality of science needed to produce an acceptable ERA report usable by risk managers to make ecological risk management decisions. Three ERA standards of performance have been developed by the authors (Scientifically Defensible Procedural Standard, Regulatory Science Procedural Standard, and Planning Procedural Standard) to reflect the spectrum of possible risk analysis requirements of regulatory agencies. The Regulatory Science Procedural Standard has numerous advantages. It offers high information payback for dollars expended, appropriately scales scope of work to recognize resource and data limitations, and focuses on obtaining sufficient information for risk management decision making.