Understanding Uncertainty and Variability Is Critical When Developing a Credible Risk Assessment

6 UNDERSTANDING UNCERTAINTY AND VARIABILITY IS CRITICAL WHEN DEVELOPING A CREDIBLE RISK ASSESSMENT 

Ineffective or unconvincing approaches to uncertainty can affect the credibility of individual risk assessments or the regulatory process as a whole. 

This has been highlighted by a number of food safety issues. For example, lack of confidence that uncertainties were being adequately dealt with has been an important factor in recent public concerns about bovine spongiform encephalopathy and genetically modified crops, especially in Europe. Uncertainty was also a factor in the earlier controversy over alar in apples (e.g., Ames and Gold 1989 Groth 1989 Thayer 1989). 

Uncertainty may also affect the credibility of ecological risk assessment procedures. In the late 1970s, the USEPA presented a risk assessment for the use of granular carbofuran on com, including a detailed list of field studies and incidents. The Eederal Insecticide, Fungicide, and Rodenticide Act Science Advisory Panel concluded there was insufficient information to justify restricted use labeling and recommended further testing. Nearly 20 years later, the accumulation of additional field studies and incidents provided sufficient evidence such that approvals for use of carbofuran were withdrawn. 

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