Evaluation of evidence and its uncertainty in qualitative pest risk assessments: the North American perspective

Abstract

Under the Sanitary and Phytosanitary (SPS) Agreement and IPPC risk management framework, measures should be based on evidence. There is however, no specific guidance about quality of evidence or treatment of uncertainty under these agreements. Uncertainty in qualitative Pest Risk Assessments (PRA) is largely dependent on the quality and reliability of information. USDA Guidelines for PRA of Imported Fruit and Vegetable Commodities (2012) and NAPPO Regional Standard for Phytosanitary Measures (RSPM) No. 40 include supplements on the evaluation of evidence. The supplements establish a framework for assessing the quality and reliability of scientific evidence. Reliability of evidence addresses the quality of information sources, the methodology used, and the degree of consensus regarding the data, rated from low to high depending on the publication sources. Applicability refers to pertinence of the information to a particular situation and is rated from low to high based on the degree of extrapolation of biological information and environmental conditions in the publication source in relation to the actual scenario in the PRA. The rating for uncertainty associated with the quality of evidence is found in a matrix that combines ratings for applicability and reliability.