learned from ecological risk assessments is that the power of an expensive test to reject or confirm a hypothesis should be evaluated before data collection. If the data are unlikely to provide a basis for rejecting or confirming a hypothesis important to the risk assessment, then it might not be worth the expense to obtain the data.
As the volume of risk assessments grows, it will be particularly important to ensure quality and consistency. Development and use of formal guidelines, training of risk assessors, and communication of examples of good risk assessment practice will help agencies and organizations to ensure quality and consistency in their applications.
Consistency and flexibility must be balanced appropriately in the risk assessment process. Consistency motivates doing risk assessments for similar situations in a similar and predictable way. Flexibility motivates departures from a standard risk assessment approach when scientific information indicates that differences are important for the proper assessment of risk. In practice, it might be appropriate to have standard or default procedures that are used when scientific information is not sufficient to motivate a different approach, and provisions for innovative exceptions that are supported by applicable scientific information.
Risk assessment should not become too rigid. Its purpose is to summarize and communicate applicable science to meet the needs of policy makers. That task by its very nature requires flexibility and creativity, not reliance on formulas or cookbook recipes evolved from past practice.
Risk Assessors and Risk Managers Need to Communicate
Managers responsible for ecological systems must be responsive to the public, and risk assessors should recognize that their task supports risk management. Risk assessment can help risk managers to explain the basis for their decisions to interested and potentially affected groups. Risk assessment, therefore, has an important function as communication.
As was stressed in a recent National Research Council report on risk communication (NRC, 1989), such communication should be two-way. To ensure that communication is effective and that public concerns are addressed, it is generally useful to involve the public while the risk