New OECD Guidance Document on Weight of Evidence for Chemical Assessment

The Organisation for Economic Co-operation and Development (OECD) has published Guiding Principles and Key Elements for Establishing a Weight of Evidence for Chemical Assessment, a new guidance document for systematic approaches to weight of evidence for chemical assessment that includes discussion of the following guiding principles:

• Formulation of problem hypotheses
• A systematic and comprehensive approach to collection, evaluation and weighing of evidence
• Uncertainty of data
• Potential bias during collection, evaluation and weighing of evidence
• Transparent documentation

The document also describes key elements of weight of evidence approaches to determine the overall strength of evidence. Taken together, these guiding principles and key elements allow non-biased decision-making that is transparent for all stakeholders.