Ecological research and environmental risk assessment are similar in that they address interesting problems by formulating and testing hypotheses. They differ in the types of problems that are interesting, the characteristics of good hypotheses to solve those problems, and the methods for rigorous testing of hypotheses. It is important to recognize the differences between environmental risk assessment and basic ecological research because confusing them can lead to ineffective risk assessment and missed opportunities to advance ecological theory. Uncertainty in regulatory decision-making about transgenic crops may be reduced more effectively by clarifying the purpose and structure of environmental risk assessments than by further research on the ecology of the crops.