National Center for Environmental Assessment, U.S. Environmental Protection Agency, 26 W. Martin L. King Drive, Cincinnati, OH 45268, USA.
Sci Total Environ. 2011 Mar 15;409(8):1406-17. doi: 10.1016/j.scitotenv.2010.12.029. Epub 2011 Jan 31.
All types of environmental decisions benefit from assessments that assemble and analyze diverse evidence. The diversity of that evidence creates complexities that can be managed using an explicit, well-designed process. We suggest two adaptations from the legal lexicon, weight of evidence and building a case. When weighing evidence, weights are assigned to each piece of evidence, and then the body of evidence is weighed in favor of each hypothesis by amassing the weights. Finally, the total weights of evidence for the alternative hypotheses are compared to determine which alternative has the preponderance of evidence in its favor. When building a case, pieces of evidence are organized to show relationships among multiple hypotheses or complex interactions among agents, events, or processes. We provide processes for weighing evidence and building a case and illustrate both approaches in a case study involving the decline of a kit fox population. The general approach presented here is flexible, transparent, and defensible. During its development, it has been applied to risk assessments for contaminated sites and to causal assessments in aquatic and terrestrial systems. It is intended to balance the need for rigor and discipline with the need for sufficient flexibility to accept all relevant evidence and generate creative solutions to difficult environmental problems.
所有类型的环境决策都受益于能够综合和分析多种证据的评估。这些证据的多样性带来了复杂性，可以通过一个明确、精心设计的过程来管理。我们从法律词汇中借鉴了两个概念，即证据权重和案件构建。在权衡证据时，为每一条证据分配权重，然后通过累加权重来权衡证据支持的每一个假设。最后，比较替代假设的证据总权重，以确定哪个假设具有更有利的证据优势。在构建案件时，将证据组织起来以展示多个假设之间的关系，或展示在事件、过程中各因素之间的复杂相互作用。我们提供了权衡证据和构建案件的流程，并在一个涉及狐尾兔种群减少的案例研究中说明了这两种方法。这里提出的一般方法具有灵活性、透明性和可辩护性。在其发展过程中，它已应用于污染场地的风险评估和水生和陆地系统中的因果评估。其目的是在需要严谨性和纪律性与需要足够的灵活性以接受所有相关证据并为解决困难的环境问题生成创造性解决方案之间取得平衡。
