In the US Supreme Court's Daubert v Merrell Dow Pharmaceuticals, Inc decision, federal judges were directed to examine the scientific method underlying expert evidence and admit that which is scientifically reliable and relevant. However, if a judge does not have adequate training or experience in dealing with scientific uncertainty, understand the full value or limit of currently used methodologies, or recognize hidden assumptions, misrepresentations of scientific data, or the strengths of scientific inferences, he or she may reach an incorrect decision on the reliability and relevance of evidence linking environmental factors to human disease. This could lead to the unfair exclusion of valid scientific evidence, particularly that which is essential to a plaintiff's case in toxic tort litigation.