Assessing the role of subjective judgment and science in environmental impact assessment: implications and options for reform

Most environmental assessment (EA) processes are based on a rational technocratic paradigm, in which experts are expected to review value-neutral scientific evidence and objectively assess project impacts. Critics argue that this model is flawed even with increased public participation because it does not recognize the significant role of subjectivity in EA and assumes that expert analysis and judgement can be objective and value free. This paper re-evaluates the assumptions of the rational technocratic model by examining new evidence from a case study in which scientific experts in two separate, but concurrent, EA reviews of the same project came to opposite conclusions even though they relied on the same terms of reference and similar information and evaluation criteria. The case study analysis provides new evidence showing that subjective judgments of expert assessors are an important determinant of the EA findings and that there is inconsistency in the exercise of subjective judgement by experts that can result in fundamentally different conclusions, even if the experts are assessing the same project and similar evidence. The nature of the subjective judgements is assessed in detail and implications of the findings for EA are discussed.